Fig. 62.—Trichoptera. Rhyacophila fenestra; the larva, shown here, is aquatic and builds no case. The larvae of some other kinds of caddisflies live in cases made of sticks and stones.
Lepidoptera
Butterflies, Moths
Insects typically with two pairs of wings, with long antennae, and with mouthparts forming a long sucking tube. The body and wings are covered with a dense mass of scales, which are characteristic of this order, [fig. 63]. The young are known as caterpillars or grubs. The larval stage in this order is well exemplified by the fairly smooth, cylindrical caterpillar of the fall armyworm, Laphygma frugiperda (Smith), [fig. 64]. Some other larvae are hairy; still others are sluglike.
Fig. 63.—Lepidoptera. A typical moth, showing scales on wings and body, and sucking tube, which is coiled up under the head when not in use. Species of this order occurring in Illinois include specimens that vary in size from 0.1 inch to several inches. The largest of these insects have a wingspread of over 5 inches.
To this order belong not only a very large number of species, but also a very large number that are especially injurious to agriculture. These include such species as the codling moth, cabbage moth, butterflies, the entire cutworm group, and a host of others. In addition, the various clothes moths, which are a constant source of loss to householders, and various species of meal moths, which cause tremendous damage to stored grain every year, are members of this order.
Fig. 64.—Lepidoptera. Laphygma frugiperda, the fall armyworm: A, egg mass on leaf; B, top and side view of individual eggs; C, adult; D, larva; E, pupae. Wing span of adult about 1.5 inches. (Drawing from U. S. D. A.)
In one group of moths, there are clear “windows” on the wings, but these are always surrounded by areas or lines of scales. A few species of the Lepidoptera are very odd in having wingless females. Examples are the bagworms and some of the cankerworms. In these species, however, the body of the female is densely clothed with scales, which will serve to identify her as one of the Lepidoptera.