Philip Cohens, age 9, of Albany N.Y., for his question:
How do you tell moth caterpillars from butterfly caterpillars?
There is no sure way to tell a moth caterpillar from a butterfly caterpillar. In the pupa state, however, there is a clue which might help you make a guess. If the caterpillar goes into his sleeping beauty stage as a hard coated chrysalis he will probably wake up as a butterfly. All butterflies pupate as chrysalises. Most moths sleep in a cocoon. If a caterpillar weaves a silken sleeping bags then he will surely wake up as a moth.
However, this is not a strict rule where the moths are concerned. The tomato worm, the tobacco worm and almost 100 of their cousins are large green caterpillars, often bedecked with a tail or horn.. They pester our crops and vineyards. When time comes to pupate, these fellows drop to the ground and become chrysalises. All of them wake up as brownish, wide‑winged sphinx moths. So, though every butterfly was ones a chrysalis, not every chrysalis plans to become a butterly. Some become moths.
Rules about which caterpillar shall be a butterfly and which a moth are even more vague. However, it seems that the fuzziest caterpillars more often turn out to be moths. The .famous woolly bear caterpillar will become a little yellow moth. This caterpillar hibernates in his furry coat and becomes a cocoon in the spring. The brown and yellow imperial moth was a fuzzy green caterpillar and the gypsy moth caterpillar wears a fringe of yellow tufts down either side. The tussock mothts caterpillar, who feeds on the leaves of our shade trees, is fringed with stiff white tufts.
Butterfly caterpillars, as a rule, do not wear heavy coats of fuzz and fur. Some, however, wear a few stiff bristles. The brown caterpillars of the lovely dark mourning cloak wears a row of red buttons down his back. The little brown larva of the beautiful buckeye butterfly wears tufts of bristles down his beck.
On the other hand, plenty of moth caterpillars also wear bristles. The caterpillar of the pink and brown silk moth is a large, pale green fallow with a double row of blue bristles down his back. The lung moth is a pale green beauty with a graceful swallowtail. The polyphemus moth is pinkish tan with a pair of blue eyes on his wings. These two moths are very different, yet their caterpillars could be mistaken for twins. Both are fat, pale green fellows with rows of bristles and little red buttons. Most caterpillars of the swallowtail butterfly and the sphinx moth have neither fuzz nor bristles.
Usually there is no resemblance between the coloring of a caterpillar end his adult moth or butterfly. The brown monarch butterfly was a tiger‑striped caterpillar. The yellow isabella .moth was once a black and yellow caterpillar.
The moths and butterflies do not make it easy for us to recognize them. They insist that we watch them grow up stage by stage and learn the life history of each individually.