See [page 270]
From a drawing by W. I. Beecroft
See [page 270]
Juvenal's Dusky-wing
Thanaos juvenalis
There are few trees which have so interesting a set of insects attacking them as does the oak. It would be a simple matter to find abundant material for a large volume by making a study of the life-histories of the various insects that live upon or within the various tissues of this tree. The leaves alone provide a home for a remarkably large number of insect species scattered through a great many orders and families. The thickened blades seem to furnish an ideal opportunity for many larvae to get their living, and they are particularly useful to those which need to make a winter nest.
By a little searching almost any time after the middle of June, one is likely to find a curious caterpillar home upon some of the oak leaves. The margin of the blade has been turned over, generally from above downward but sometimes from below upward, and has been fastened down to the main expanse of the blade by means of golden threads; commonly this fastening is not continuous but is more or less intermittent, so that the turned-over margin is likely to have an irregular border where it joins the blade. Inside of this tubular construction a rather unusual looking worm-like caterpillar is probably to be seen. Late in the season it will probably be nearly an inch long, with a smooth greenish body and a head that may be a bit brownish and more or less marked on the sides with orange tones.
This is the larva of one of the most widely distributed Skippers—Juvenal's Dusky-wing. The species is found from southern New Hampshire west to the Great Plains and south to the Gulf of Mexico. In most localities it is seldom abundant but yet is so general that it may be found by almost every persistent collector. The wings expand about an inch and a half and are of a dull brownish color, more or less marked with darker and lighter spots. Toward the northern limits of its range there is but one brood a year but farther south there are two, although it is not improbable that some of the caterpillars of the first brood remain unchanged throughout the season, so that the insect is both single- and double-brooded in the same locality.