( Originally Published 1917 )
The true butterflies are so distinct in their structure and many of their habits from the Skippers that the most careful students of the order are pretty well agreed in making the two great superfamilies—Papilionoidea, the true butterflies, and Hesperioidea, the Skipper butterflies, The latter includes these two families:
The Giant Skippers (Megathymidae).
The Common Skippers (Hesperiidae),
These insects as a whole are distinguished from the higher butterflies by their large moth-like bodies, small wings, hooked antennae (except in the Giant Skippers), by having five branches of the radius vein arising from the large central cell. The larvae spin slight cocoons in which to pupate and the pupae are rounded rather than angular.
The two families are readily distinguished by the differences in their size and the structure of the antennae. The Giant Skippers measure two inches or more across the expanded wings and have comparatively small heads, with the clubs of the antennae not pointed or recurved. The Common Skippers are smaller, and have very large heads with the antennal clubs drawn out and recurved.
THE GIANT SKIPPERS
Although large in size, the Giant Skippers are few in numbers. Only one genus and five species are listed for North America, and practically all of these are confined to the Southwestern states and Mexico. Some of them extend as far north as Colorado and as far east as Florida.
So far as the story of its life is concerned, the best-known species is the Yucca-borer Skipper (Megathymus yuccas) which was carefully studied by the late Dr. C. V. Riley. As will be seen from the picture above which represents the adult, natural size, this skipper has a body so large as to suggest some of the heavy-bodied moths. The wings are dark brown, marked with red-brown spots and bands. They fly by day and when at rest hold the wings erect.
These adults lay eggs upon the leaves of Spanish needle or yucca. The eggs soon hatch into little caterpillars which at first roll parts of the leaves into cylinders, fastening the sides in place by silken threads, and later burrow into the stem and root, often making a. tunnel a foot or more deep. Here the caterpillars remain until full grown. They are then nearly four inches long and half an inch in diameter. They now pupate in the top of their tunnel and in due season emerge as adults.
THE COMMON SKIPPERS
The Skippers are the least developed of the butterflies. They show their close relationship to the moths both by their structure and their habits. The larvae make slight cocoons before changing to chrysalids, and these chrysalids are so rounded that they suggest the pupae of moths rather than those of butterflies. The common name Skippers-is due to the habit of the butterflies—a jerky, skipping flight as they wing their erratic way from flower to flower.
In North America the Skipper family includes nearly two hundred species grouped in about forty genera. From this point of view it is the largest family of our butterflies, but on account of the small size and limited range of most of the species it has by no means the general importance of such families as the Nymphs, the Swallowtails, or the Pierids.
The Skippers are remarkable for the uniformity of structure in each stage of existence. The butterflies have small wings and large bodies. The broad head bears large eyes without hairs, but with a tuft of curving bristles overhanging each. The antennae are hooked at the end and widely separated at the base. Each short pal-pus has a large middle joint and a small joint at the tip. The fore wings project out at the front angle and the hind wings are folded along the inner margin. There are six well-developed legs in both sexes. The colors are chiefly various tames of brown, dull rather than bright, and many of the forms resemble one another so closely that it is difficult to separate them.
The Skipper caterpillars have stout bodies and are easily known by the constricted neck. Most of these have the habit of making nests from the leaves of the food plants, weaving them together with silken threads. In a similar way each also makes a slight cocoon when it is ready to change to a chrysalis.
The Skippers found in eastern North Afnerica are corn-' monly grouped into two types—the Larger Skippers and the Smaller Skippers. The characteristics are given in the paragraph immediately following and the one on page 278.