I'd say the color changes take place after the molt. Think about gulf frits, and how their spines are clear right after they molt, then the black color gradually appears. I'm no scientist, but in my observations, the color change comes during or after the actual molt, certainly not before. MissSherry P.S. It's funny you should post about molting. I noticed a cicada - the regular summer type - on a piece of cudweed today, with the old skeleton just below it. The cicada was clear colored and didn't appear able to fly. When I came back to the same cudweed a few hours later, the wings had darkened and didn't look so fragile. I'm clueless about cicada life cycles, but it looked like this critter changed color after molting, too.

Thanks! My sphinx cat "disappeared" today, and I found it underneath the paper towels and foam rubber. I offered it some more food, but it refused and kept wandering. I noticed that it was yellowish, the color that many sphinx and big silk moths turn before they make their pupa. Well, DUH, it finally occurred to me that that's just what my cat was trying to do, so I got a container, put some leaves in it plus the small glass jar with the stem of yaupon in it that it was eating, put the cat in it, and it proceeded to go under the leaves and I assume, pupate. So, obviously it couldn't be a rustic sphinx, it's not nearly big enough, and I think the horn color is wrong. I looked through the sphinx moths on Bill Oehlke's site, and the page on the pawpaw sphinx had a picture of a cat from North Carolina that looks just like mine. It listed pawpaw as a host, plus lots of hollies, like Ilex glabra, I. decidua and I. coriacea, all of which grow on my property - he didn't list I. vomitoria, but it's very much like I. decidua, just evergreen, not deciduous. The horn is purple or red and blue, like mine also. Interestingly, the pictures of adult pawpaw sphinx moths are variable in coloring, some reddish brown and others very dark brown/black. The website said that in Louisiana they have two generations, the last one being in September, so I guess that's what this one is, meaning that my cat should overwinter. I've linked the Bill Oehlke site. Sherry Here is a link that might be useful: PawPaw Sphinx

Susan, It's sad to see them run out of food. I had to watch the "parsley famine" after my black swallowtail caterpillars finished it off. I didn't see the dead cats. I did see the larger ones eating the parsley stems, that they had rejected before. Hope you find homes for them. Maybe it's one way nature controls/balances populations. Including humans. Scary thought. Gayle

You are confused for some reason, are confusing the issue. Clearly, the OP had identified the Tobacco hornworm, Manduca sexta. Do you not believe that someone new to the gardenweb or new to gardening can utilize the internet in a useful manner? I know...it seems to be rare, but I am proud of David. Sphingidae is a large family of moths. They are ALL correctly called Sphinx moths. Our OP plucked the caterpillars from his tomato plants and went to work finding a proper ID. The caterpillars of most (not all) Sphinx moths are hornworms and as a family, can be found on many kinds of plants. They tend to be host specific. Now, Kimmsr.....there are hornworms that feed on Solanaceous plants. I have never seen Tobacco hornworm on anything but a tomato or datura or pepper. I have also never seen nor heard of nor read of any other kind of hornworm (Sphingidae) on those plants. I hope that you have a better understanding, now. It can be confusing, for sure. But understanding the host /pest relationship with this particular moth family is extremely important. One can pretty much ID a hornworn if the host plant is identified....no picture of the caterpillar required. In this instance, we had an OP who was one step ahead of the usual 'newbie '. David used the internet. All he wanted to know is if he planted some tobacco plants would the Manduca sexta lay eggs on those and stay away from his tomatoes.