This is a large order of insects and one of the best known. It contains some of our most important pests; such as the bollworm, armyworms, cutworms, codling moth, clothes moth and cabbageworm.
Lepidoptera usually have four well developed wings covered with overlapping scales as adults. A few adult Lepidoptera have reduced wings or none at all. Mouthparts of the adults are formed for sucking but some have reduced or non-functional mouthparts.
Butterflies generally fly during the day and can be recognized by the clubbed antennae. Skippers are much like butterflies but have the end of the antennae hooked rather than clubbed. Moths generally fly at night but there are exceptions. Moths have antennae that are linear or feathery but not clubbed.
Immature stages (larvae) are known as caterpillars. Names like cutworms, armyworms, hornworms and many others apply to groups of caterpillars that may be related taxonomically or by similar biology. Their mouthparts are formed for chewing. The well developed head capsule has short antennae. On the front of the face of caterpillars is an groove or suture shaped like an inverted “V.” On caterpillars there is a second suture called an adfrontal suture just under the “V.” Almost all have crochets (small hooks) on the prolegs even if the prolegs are reduced. These hooks help the caterpillar hold onto the substrate. Caterpillars feed on foliage, stored products, linens. Some are leafminers and a few are borers in herbaceous and woody plants.
Most Lepidoptera feed on leaves of plants in the larval stage. Some caterpillars bore in plant stems, others are leafminers and a few are ever predators. All Lepidoptera have complete metamorphosis. Microlepidoptera are often under 1/4 inch, the largest moths and butterflies are over 3 inches.