Monday, February 3, 2020

A Collection History Mystery

It has been a busy winter! Among several projects, besides my day job, I have been developing an Access database of my insect collection. It is slow progress and although I have over 800 specimens cataloged so far, I have another estimated 4000-5000 to go. One reason it is taking a long time is because I have been investigating and learning all kinds of information about a portion of my collection that was given to me nearly 19 years ago.

The story begins when I was around 12 years old. My life-long passion for insects was turning into a dedicated study with a focus on butterflies and the start of a collection. My first mentor was Mr. Terry Ely, a friend from church and the local USDA plant quarantine officer. Terry was primarily interested in moths but had a collection of many insects from all over the world and gave me tips on how to preserve the bugs I was starting to collect. He gave me my first Banded Alder Borer beetle (Rosalia funebris), my first California Tortoiseshell (Nymphalis californica) butterfly, a giant grasshopper he collected in Guayaquil, Ecuador, and any other interesting insects he came across in his work. When I found a dying female poplar sphinx (Pachysphinx occidentalis) in my backyard that was tattered but so exciting to 14-year-old me, Terry brought me a perfect specimen less than a month later that he had found while working in eastern Washington. Throughout these few years, Terry told me stories of his childhood, that his family would take trips across the country, that his mother had corresponded and traded butterflies and artifacts with people all over the world, including a prince, and that Terry had collected a lot in New Hampshire. I loved hearing the stories, but as a teenager I didn’t think to ask questions and learn more details about the collection I was hearing of.

My insect collection circa 2000, after 5 years of collecting and a few dermestid beetle infestations. The giant grasshopper (below center) and one of the moths (top right corner of the upper left display) were collected by Terry Ely.

One day in the summer of 2001, Terry told me that he was retiring and moving to Arizona, that his mother’s collection had already been moved long distances at least twice and was in rough shape, that he couldn’t see doing that again, and that he knew I would treasure and care for it, if I was willing? I was shaking with excitement and don’t remember much else of that conversation, but with permission from my parents, the collection was mine! We met at his office and I was blown away as we emptied a large metal cabinet with drawer after drawer full of butterflies and moths. Fifteen drawers, 18x22 inches each of solid oak with glass lids. I was told that the cabinet and drawers had been surplus from a university back east. 
Antique cabinet and oak drawers from Terry Ely.

Once home, I began the painstaking task of evaluating the specimens and repairing everything as best as I could. Many specimens were damaged from previous moves, a little dermestid beetle damage, and several rusty pins and moldy specimens from exposure to humidity at some time in the past. I replaced as many pins as I could, gently cleaned off dried mold with a soft paintbrush, and became an expert at carefully matching up and gluing broken wings and bodies. Most of the specimens didn’t have any identification labels, only general locations and dates at best, thus I had to comb through books to identify the hundreds of butterflies, organizing them into taxonomic groups, rapidly widening my ability to recognize key features helpful to securing an identification. A couple years went by and then I received news that Terry had passed away suddenly at his home in Arizona. Although I lost a mentor, a new chapter opened when in the same year I met Jonathan Pelham, who quickly filled the role of mentor and later colleague. However, without Terry to ask questions of, I had to piece together the history of my collection solely on his few stories and the tidbits I could gather from the specimen labels.

In the early years, internet searches came up empty for Terry Ely, his mother, Rachel, and a few of the names on the specimen labels. Over time I came to recognize certain labels as coming from the same person, either by the handwriting, the location and date, or the style of label. This allowed me to piece together little vignettes of history since one label might include a person’s name with a date and location that matched other labels with the same data but no name. One specimen still in a paper triangle bears the stamp of “J. C. Hopfinger, Brewster, Wash.” with handwriting in pencil of “E. anicia hopfingeri”, which I’ve been told matches Hopfinger’s handwriting seen in other collections. Considering that Hopfinger traded widely it is no surprise one of his specimens ended up in Rachel Ely’s collection.
Euphydryas anicia hopfingeri specimen from J. C. Hopfinger.

One piece of the puzzle continued to confuse me: Terry had talked about New Hampshire so much that I had assumed that’s where he grew up, yet many of the specimens with labels in Rachel’s handwriting were from Wisconsin. Recently my curiosity climbed again and I started searching the internet for any trace of Rachel’s history or information on some of the other names on the labels. I was able to find a few tidbits on two of the names, both associated with the University of New Hampshire, but it was my mom who had the brilliant idea to search for Rachel Ely along with the keyword “lepidoptera” instead of the “butterflies” or “New Hampshire” that I had been trying. Up popped a link to an old Lepidopterists' Society archive and the floodgates were opened! Turns out that Rachel was a member of the Lepidopterists' Society from 1951 to at least 1955, first under her married name of Mrs. Frank Ely and then as Mrs. Rachel Ely after her husband passed away. Through the archive I discovered she was actually from Endeavor, Wisconsin and after searching with those additional keywords, I came across a newspaper article (Wisconsin State Journal, November 23, 1952, section 2, page 13) that talked about this extraordinary family of Rachel, 13-year-old Terry and his younger sister Cindy, who lived in a house that was so like a museum of natural history artifacts that the local schools would take kids to visit it. The article has pictures with some of the butterfly specimens in the background, and I easily recognized ten specimens that are in my collection, and several others that resemble specimens in my collection but are too small to positively identify to a particular specimen. The article also mentions that she traded curios with many foreign collectors, including an African prince, corroborating my memory of what Terry told me.

Newspaper photo of some of the Ely Collection in 1952. Some of the butterflies within the white outlines (middle/right) are easily recognizable as specimens Terry gave me, see below.
Ely Collection specimens seen within the white frame on the right in the newspaper image.
Ely Collection specimens seen within the white frame on the left in the newspaper image.

Further searching revealed that Rachel wrote a short note on finding and rearing Hemileuca maia in Wisconsin that was published in the LepSoc News in 1954. Learning that she was a member of LepSoc at the same time as J. C. Hopfinger, I wondered who else might have been a member she had traded specimens with. Several of my specimens are from Malta, all with typewritten labels on glassine paper, so I started with those. According to the LepSoc membership lists from 1951-1955, the only member from Malta was Anthony Valletta. A quick internet search showed he lived from 1908 to 1988, was a Fellow of the Royal Entomological Society, had the largest collection of butterflies and other insects in Malta, and wrote several nature books including The Butterflies of the Maltese Islands.

Other names on specimen labels have ties to the University of New Hampshire, which appears to have been where Terry went to college, although I haven't been able to confirm this. Most of the moths in my collection were collected by him there circa 1963. I suspect that some New Hampshire moths with older dates were given to him by his university acquaintances, including a handful of specimens with dates ranging from 1889 to 1919!

In an incredible twist of the story, I also discovered a tie to my own northwest Lepidopterist connections. Around 2006 or 2007, I began attending the Northwest Lepidopterists’ Workshop in Corvallis (OSU) each fall, where I met Ann Albright. Her husband Ray had passed away a few years prior and she was giving away hundreds of papered specimens from their many collecting trips. I jumped at the chance to add to my collection and brought home several dozen specimens from Oregon, Idaho, Montana, Arizona and elsewhere. All had typewritten labels with handwritten species identifications. During my recent searches through the LepSoc membership directories, I noticed that Ray Albright of Dayton, Oregon was listed as a member during the same time as Rachel Ely. I remembered that I have some specimens from Oregon in Rachel’s collection and seemed to recall Dayton as a location on one of them. Sure enough, a papered specimen of Coenonympha tullia from 1957 has “Dayton, Ore” written in pencil. Likewise, a specimen of Speyeria zerene gloriosa from O’brien, OR in 1958 and one of Parnassius clodius baldur from Mount St. Helens, WA in 1956 bear the same handwriting. The handwriting looked very similar to the specimens I had obtained from Ann. I sent the images to her and she confirmed that it does look like Ray’s handwriting, that he collected in those locations, but these were dated before she knew him so she couldn’t confirm if Ray traded with Rachel or if Rachel might have obtained these from a mutual acquaintance.

Albright specimens: the top three in paper envelopes were collected by Ray and found in the Ely Collection. The bottom specimen was collected by Ray and Ann and acquired by me from Ann. There are some slight differences between the handwriting but that is not surprising considering there is a 40-year gap between them.

Continuing my investigation into the Ely Collection, I ran a search for “Rachel Ely” on SCAN (scan-bugs.org), which turned up five specimens in the Milwaukee Public Museum (MPM):
  • Smerinthus jamaicensis, July 1952 (has a note that reads “this specimen photographed for Sphingidae of Wis.”)
  • Dolba hyloeus, June 29, 1958 (has a note that reads “this specimen photographed for Sphingidae of Wis.”)
  • Hemileuca maia, October 4, 1953 (x2)
  • Catocola whitneyi, July 1958
I reached out to the collection manager to request images or more information about those specimens and she emailed me images several days later. In addition to the labels that looked exactly like Rachel’s labels in my collection, the specimens also had labels stating they were from the William E. Sieker collection, confirming the following details.
While waiting for the photos, I searched for the book Sphingidae of Wisconsin without any luck, so I started reading about the museum, hoping to pick up any other clues. I quickly recognized the name of one of their major donors, William E. Sieker, and how he had one of the most complete collections of worldwide Sphingidae which was donated to their museum. I remembered Rachel had mentioned him in the Hemileuca maia note published in the LepSoc news: she and Sieker netted a bunch of H. maia after she and Terry had found numerous maia larvae crossing the road earlier in the season. In researching more about Sieker, I learned that he founded the Wisconsin Entomological Society (WES). Then I came across his obituary and in the same 1982 WES newsletter there was a list of upcoming speakers, one of whom was Michael Collins, a Saturniidae researcher I know. I emailed him to see if he could shed any light on the Sphingidae of Wisconsin book or if he might have even known Sieker. He responded that while he had briefly corresponded with Bill (Sieker) about silk moths, they had never met, but he put me in contact with Les Ferge from Wisconsin. Les informed me that Bill mentored him from 1971 until Bill’s death, Bill spoke of Rachel occasionally and lamented her tragic early death from an automobile accident. According to Les, the Sphingidae of Wisconsin was a manuscript Bill was working on until his death, but it was never published. Les also suggested that my sphinx moth specimens from Door County, Wisconsin were actually collected by Bill, who owned a vacation cottage in Door County. He said that Bill would run lights and collect moths up there and frequently traded or gave specimens to people, so it is more likely that he and Rachel traded specimens rather than Rachel collecting the Door County specimens herself. This would explain the five specimens of Rachel’s in the MPM, which were donated to the museum as part of Bill Sieker’s collection after his death.

Sphinx moths in Rachel's collection that were presumably collected by Bill Sieker in Door County, Wisconsin.

Ely Collection contributors are as follows with information found through public records searches, LepSoc archives or museum websites:
  • Rachel Ely: 1911 (WI) – 1959 (NH), lived in Endeavor, Marquette County, WI.
  • Terry Ely: 1939 (WI) – 2004 (AZ), also lived in NH, ME, WA.
  • William E. (Bill) Sieker: 1911 Sep 5 – 1982 Jan 22, lived in Madison, WI and had a vacation home in Bailey's Harbor, Door County, WI, knew Rachel, traded a few specimens and collected with her.
  • Auburn E. Brower: 1898 May 22 – 1994 Apr 15, lived in Augusta, Maine, associated with Maine Forest Service (which is noted as a "sister institution" of University of New Hampshire), LepSoc member same time as Rachel. I also found a paper on the Lepidoptera of Maine that has Terry Ely listed as the source of one of the records.
  • Robert L. Blickle: 1913 Nov 12 – 2002 Dec 30, University of New Hampshire, retired from UNH in 1979, would have been a professor at the time Terry apparently attended.
  • William F. Fiske: 1876 – [disappeared in Africa in 1913], studied at the New Hampshire College of Agriculture and Mechanical Arts (later University of New Hampshire), during the 1890s, and became an entomologist. He was the assistant entomologist for the New Hampshire Experimental Station, 1897-1901; assistant entomologist for the state of Georgia, 1901-1903; assistant in forest investigations, 1903-1906; in charge of the Gypsy Moth Laboratory (Melrose Highlands, Mass.), 1906 May-1913 January; and United States Department of Agriculture, special investigator of sleeping sickness in Africa for joint commission of Royal Society and British Colonial Office, 1913- . He was also a member of many societies and clubs. He apparently disappeared while on his investigation in Africa.
  • Clarence Moores (C. M.) Weed: 1864 Oct 5 – 1947 Jul 20, Professor of Zoology and Entomology in the NH College of Agriculture and Mechanic Arts, Entomologist of the NH Experiment Station, and Associate Editor of the American Naturalist. Bachelor of Science, Michigan Agricultural College, 1883, Master of Science, 1884. Doctor of Science, Ohio State University, 1890. Entomologist and botanist, Ohio Experiment Station, 1888-1891. Professor zoology and entomology, 1891-1904, entomologist in Experiment Station, 1891-1904, New Hampshire College Agriculture and Mechanics Arts; instructor, 1904-1922, principal, 1922-1932, president 1932-1935. Associated with S. Albert Shaw and William F. Fiske in publications.
  • Charles P. Kimball: 1937 Feb 7 – 2010 Nov 16, his collection is cited as being acquired by the Museum of Comparative Zoology – Harvard. Weed & Fiske publication Butterflies of New Hampshire mentions some records from "Kimball," indicating all three men knew each other.
  • S. Albert Shaw: 1856 Aug 23 – 1944 Apr 6, his collection was donated to the University of New Hampshire and their website states that he was an active collector of insects, especially Diptera, from 1890 until 1934. C. M. Weed mentions him as a colleague in publications.
  • Wallace J. Morse: 1916 – 1999, affiliated with the University of New Hampshire (possibly a professor when Terry attended?), his collection of Odonata is listed as a major component of UNH collections.
  • John C. Hopfinger: 1888 Mar 30 – 1961 Jun 7, born in Kastin Austria, came to the US in 1906 and lived in Brewster, WA. LepSoc member same time as Rachel.
  • Walter H. Freeman: Camarillo, CA, LepSoc member same time as Rachel.
  • Anatole S. Loukashkin: 1902 Apr 20 – 1988 Oct 6, born in Liaoian, China (father worked for the Chinese Eastern Railway). He worked as a curator of the Museum of the Society for the Study of Manchuria in the 1930s. Upon arrival in the United States in 1941, he transferred his skills to the California Academy of Sciences. One moth specimen in Ely collection has a label with his name and “Korea” written on it.
  • F. H. Schade: on a Danaus erippus specimen from Paraguay, likely refers to Dr. Francisco Schade who apparently has a namesake zoological museum in Paraguay, no other info found (he was not a LepSoc member). Based on the trend of Rachel apparently communicating with fellow LepSoc members, it is likely that she obtained this and other South American butterflies and moths via trade with one or a few LepSoc members rather than from Schade himself.
  • Anthony Valletta: 1908 Dec 21 – 1988 Dec 8, lived in Birkirkara, Malta, well known educationalist, lepidopterist and naturalist; Fellow of the Royal Entomological Society. Published several small guide books for the Maltese Islands, LepSoc member same time as Rachel.
  • Dr. Hermann Wilcke: Kössen, Tirol, Austria, LepSoc member same time as Rachel.
  • Josef Wolfsberger: 1918 Jul 5 – 2001 Jul 27, if my German translation is correct, he was the curator of Lepidoptera at the Zoologische Staatssammlung München = Bavarian State Collection of Zoology, and a well-known collector. I wonder if Rachel reached out to Dr. Wilcke through LepSoc and obtained specimens from him, and he might have given her one from Wolfsberger.
A sample of specimens collected by a few of the people listed above:
Colias harfordi collected by Walter H. Freeman
Sphinx moth collected by Josef Wolfsberger
Danaus erippus (Southern Monarch, a different species than the Monarch) collected in Paraguay by F. H. Schade
Assorted sphinx moths with the same style of labels: paper with faint hand-drawn lines and neatly written data in pencil. There are a few butterflies in the collection with the same style of label. If you can't read these, they are from Germany, Venezuela, Yucatan (Mexico) and Kyoto (Japan).

Colias palaeno from Wurtemburg Germany in 1933, no collector given, handwriting looks like Rachel's, so this is probably something she got in a paper triangle and copied the data to a new label.

Once all the specimen data is entered into my database, it will allow me to query and compare all the records and possibly identify other relationships, such as multiple specimens from the same date or location. What began as a simple yet generous gift of this collection has led to so many amazing discoveries and I can’t wait to uncover more of the history!
If anyone reading this recognizes the names or may have other pieces of the puzzle, please contact me.

Tuesday, January 21, 2020

Comments and communication

Hi folks, I'm preparing an extra-long blog post to come soon, but just noticed a backlog of comments some of you submitted (along with lots of spam) that have been stuck in my moderation settings waiting to be published. I used to get an automatic email as soon as someone commented on a post, but Blogger keeps deleting my email in that setting (I added it back in, again). So sorry! I did not mean to ignore anyone. If you have a question, please don't hesitate to use my public email address, posted in the sidebar on the left, as you will likely receive a faster reply! To those of you who left comments, I've now published them. Thank you for your support!

Tuesday, September 3, 2019

Late season butterflies

A few late summer butterflies to wrap up the season...all from August 31-September 1, 2019 in Kittitas County, Washington. Note the sage-green eyes on the metalmarks, aren't they gorgeous?

Apodemia mormo, Mormon Metalmark, Schnebly Canyon, Kittitas County, WA
Apodemia mormo, Mormon Metalmark, Durr Road, Kittitas County, WA
Apodemia mormo, Mormon Metalmark, Durr Road, Kittitas County, WA
Coenonympha tullia, Ochre Ringlet, Schnebly Canyon, Kittitas County, WA
Speyeria coronis, Coronis Fritillary female, Schnebly Canyon, Kittitas County, WA

Saturday, June 8, 2019

Wednesday, May 22, 2019

Rearing butterflies and moths

With the rearing projects I've done over the years, I've never written out everything I do or problems I've learned from. The following instructions are based on my personal experiences rearing various species, mostly in the Saturniidae family (giant silk moths). These notes are aimed towards the casual rearer, someone who may have found a caterpillar or wishes to raise a few eggs through to adults.

Large-scale rearing operations require established host plants in order to support numbers of caterpillars in the fifties or hundreds. In order to contain the larvae and protect them from predation and parasitism, people usually place large mesh sleeves over branches that are tied off at both ends, or occasionally they may have large walk-in mesh cages with potted bushes.

My rearing operation is what is considered a small-scale operation, with less than 40 larvae of any one species, mostly fed with cuttings of their host plants. If the plants are small and something I can buy at a nursery, like kinnickinnick or other forbs, I'll keep the whole plants in my rearing cages, which are in three sizes: 12" cubes, 14x14x24" and 24x24x36".

Eggs
Place a paper towel in the bottom of a plastic or glass container (I often cut to fit) and then place the eggs on the towel. Keep the lid of the container on, opening it once every day or two when you check the eggs. Keep in mind these critters are tiny and need relatively little oxygen, so you won't suffocate them in an airtight container. My preferred container size is a square plastic Rubbermaid sandwich container, although I've used a variety of containers, including small glass canning jars.

In some species, eggs change color or develop a pattern a day or two before the larvae hatch. Sometimes you can even see the caterpillar through the eggshell within 24 hours of them hatching. Eggs of some species overwinter (these are usually laid in the fall), but eggs of most species will hatch in 7-14 days, with most in my experience hatching around 10 days after being laid.

Rubbermaid sandwich container used for hatching eggs and feeding 1-3 day old larvae

Newly-hatched caterpillars
Within a couple hours of the larvae hatching, place one or two small sprigs (or leaves if it's something big like madrone) of their host plant on the paper towel in the container. If it is an airtight container, the cutting will usually remain fresh for 24-48 hours without any additional moisture. The paper towel helps absorb excess moisture that could lead to fungal growth which can kill the caterpillars.

Reasons I don't put the newly-hatched larvae immediately into a large cage on branches of host plant:
  • If I'm not sure they'll eat a particular host, it gives me the chance to test a few options in small amounts and be able to see if they're eating one or the other.
  • New larvae don't stay on the host plant very well during the first 24-48 hours, they often wander. In the wild, they would typically be on a large plant or tree so would have lots of room to crawl around and still be on the host. If I put them in a large cage right away, they sometimes fall off the cut branches or crawl off one and onto the cage walls, then crawl all over the cage trying to find the food again.
  • The airtight container keeps the food fresh for at least 24 hours without requiring it to be wrapped in a wet paper towel or placed in a vase with water. Larvae are very susceptible to drowning, especially when they're so tiny that it doesn't take much water.
All of the above gives the larvae the best chance at survival. Once they are eating well, they're less likely to wander off of the plant cuttings. This is when you should move them to the main rearing cage. They should not be kept in the airtight hatching container for more than 2-3 days or the humidity may build up too much and cause bacterial or viral infections, or the food can become moldy.

Rearing caterpillars in mesh cages
Rearing cages come in a variety of shapes and sizes. I use the collapsable (aka popup) style with fine mesh on all sides except one side that is made of clear vinyl for easy viewing. These cages allow good air flow while keeping even the tiniest caterpillars contained and also protected from parasites and predators. Small 10-12 inch cube cages are excellent for portability (I always keep one in my truck in case I find something in the woods I want to take home!) and for rearing small batches of larvae. I use medium cages (14x14x24) for most rearing and two large cages (24x24x36) when I have particularly large cut branches and/or caterpillars, like when I reared the Ceanothus Silk Moths on Douglas-fir and Pacific Madrone last year.

Some of these pop-up cages don't sit flat very well because of the curved wire frame. This can be a problem if your plant cuttings are top heavy or in a vase that is easily tipped over. I get around this by using large, flat-bottomed containers such as quart or half gallon canning jars and being careful to place the cage on a hard surface like a table or supported by walls in a corner of my porch or living area. If you or someone you know is handy with wood-working, you might try cutting a piece of plywood to fit the inside of the bottom of your cage to stabilize it. You would need to curve or otherwise blunt and sand the corners to fit properly so the board doesn't wear holes in the mesh.

Place an old towel or layers of paper towels on the bottom of the cage to collect the frass, this way you can easily roll it up and shake it out in the garbage to keep the cage clean. You should do this every few days or at least whenever you change the plant cuttings, to keep the caterpillars' environment clean.

Don't overcrowd the caterpillars, this can lead to viruses or other problems killing them or resulting in otherwise unhealthy larvae.

Keep the cage in a well-ventilated area, outside exposed to the natural temperatures is best if you have a covered space, but I usually keep them inside next to a bright window.

The most critical part of rearing caterpillars is keeping the food fresh.

Live plants
If at all possible, feed your caterpillars on potted plants inside a medium to large rearing cage. Many host plants are available at nurseries, even if they aren't the exact native species your butterfly or moth is used to. There are a few native plant nurseries in the northwest that are also good sources.
Be mindful of how the plants have been grown and cared for. I've read that most plants aren't sprayed at the nursery where you're buying them, only where they were grown, which would wear off by the time you buy them (I bought some plants recently that specifically said they were only grown with biological control methods, like ladybugs to control aphids). However, milkweed plants being sold by some big box stores a couple years ago were discovered to have tags indicating they had been grown with systemic neonicotinoids, a very deadly pesticide to insects that can remain in the plant for months. I don't know if this is still being done, but just be careful to read all the tags on the plants prior to purchase.

Cut plants
In most cases for small-scale rearing, you will be dealing with cut branches. I manage these in two ways. The critical part is ensuring that your caterpillars can't access the water source and drown! This is a common problem, so you are not alone if you lose a couple caterpillars this way, but it is nonetheless devastating.

Method 1: wrap the cut end with soaked paper towels and place in a plastic baggie tied off tightly with a rubberband or twist tie. I do this for small to medium twigs, such as when I'm starting off some young caterpillars or rearing a species that has very small larvae even when they are full grown.

Method 2: use a vase or other container with water, plugging the opening very tightly with paper towels or plastic wrap. This can make it difficult to change out the stems, so I usually do this when I have a lot of caterpillars requiring large branches that take up a lot of water, or if I am using host plants that do very well as cut stems for long periods of time, such as willows or evergreen trees and shrubs. The easiest way to do this is with a narrow-necked vase that you can put 1-3 stems in it and then stuff paper towels around any remaining gaps in the vase to keep the larvae from crawling down the stems and drowning in the water. If you have larger branches and need a bigger container, I like to use quart or half gallon glass canning jars, but these can be more difficult to seal up. If you put so many branches in the jar that it only needs a few gaps closed off, it's not hard to use pieces of paper towel. Sometimes I cover the top of the jar with 2-3 layers of plastic wrap and a rubberband, then pierce the plastic layer with the stems, then seal up any loose gaps or rips with pieces of paper towel.
If you stuff a lot of paper towel into the gaps to the point that it starts absorbing water from the jar, it can open up some of the holes, so keep an eye on that and stuff more paper towels in it.

No matter what, check your caterpillars frequently and watch for any that may slip through a gap you missed. If you find one early enough, you may be able to revive it if you put it on a dry paper towel and very gently blot it.

Plants that do well as cuttings can be kept fresh for up to two weeks. If the cuttings start dropping leaves or become brittle, replace them as soon as possible to keep your caterpillars healthy. Most cuttings can be kept in the refrigerator for a week or two and stay very fresh, just wrap the cut ends in wet paper towels and place the entire cutting into a gallon ziploc bag or even a small trash bag, seal it most of the way, then blow into it to inflate the bag and quickly seal the rest of the way. I've had great success with this method! I'll also keep extra cuttings in a bucket with water to change out the cuttings in the rearing cage through the week for larger projects, such as the Ceanothus Silk Moths I reared on Douglas-fir and Madrone last year.
If you can obtain fresh cuttings more often than once a week, that is of course ideal, but if you can only gather the cuttings on weekends, just make sure to plan ahead and gather a little more than you think you'll need for the week.

Moving the caterpillars
Use a small paintbrush, like a watercolor brush, for moving the larvae to fresh food. Be gentle and slide it under them from the side, kind of rolling it a little and gently pry them off the stem they're on. You may need a larger brush if the larvae are larger than an inch long and have stinging spines. Otherwise with most species, once they're about an inch or bigger, they become easier to move by hand or with a small stick. Sometimes I just clip off the section of stem they are on and prop it on the new cuttings, often they'll immediately start to crawl onto the fresh leaves.
Count your caterpillars! This ensures you've accounted for all of them when you move them to fresh cuttings. They can be easy to miss, so usually I remove the old cuttings and clip off all the leaves or pieces of stems they are attached to and place them in a temporary "holding pen", then once the fresh cuttings are ready, I transfer all the larvae to the new branches.

Preparing for pupation
Once your caterpillars have finished eating they will start crawling around the cage looking for a place to pupate. Butterflies will usually hang from or otherwise attach their chrysalis to stems of the host plant or the inside of the rearing cage. Moth species that spin cocoons will spin up in the branches of the host plant cuttings. When they start doing this, do not replace the cuttings or disturb the caterpillars, keep them in a spot where they won't get jostled around. Once the cocoons are formed, wait at least a week before moving them, to allow time for the pupa to form. If you know the cocoons or butterfly chrysalids will overwinter, you may carefully cut the twigs they are attached to and prepare them for overwintering (I'll save that for another blog post). Otherwise, just dump out the water in the jar but keep the twigs in the cage and wait for the adults to emerge.

If you are rearing a moth species that pupates underground without spinning a cocoon, watch out! Those caterpillars will chew right through your cage and hide in all corners of your house! If you have earth-pupaters (like sphinx moths, a few Saturniids and others), keep a close eye on the larvae as they reach maturity and as soon as they start crawling around the cage for a day without eating, immediately move them into a plastic or glass container filled with crumpled paper towels. A five gallon bucket with a lid works well for this. You can provide them a pot of soil at least 6 inches deep, but you'd need to make sure the soil was free from fungus and potential parasites. It will take a few days for the caterpillar to develop into the pupa, so leave them in a quiet dark place for at least a week. If they are a species that overwinters as the pupa, place them in a container for the winter (I'll discuss this more in a future post on overwintering), otherwise, place the pupae back into your rearing cage to await the adults in a couple weeks.

I'm open to other rearing tips, so please share your experiences!