Butterflies Worth Knowing Part 25

=The Tailed Blue= _Everes comyntas_

The tiny, threadlike, white-tipped tail projecting from the hind angle of the hind wings distinguishes this species at sight from any other found in eastern North America. The species, however, occurs clear to the Pacific Coast and ranges north and south over most of the northern continent. The small slug-like caterpillar feeds upon the flowers of various clovers and other legumes.

=The Silvery Blue= _Nomiades lygdamus_

It would be a distinct privilege to work out the life-history of this exquisite little b.u.t.terfly. Although the adult was described as long ago as 1842, the early stages seem to be still unknown. The species occurs in the South Atlantic states, extending west as far as Wisconsin.

_Synopsis of the Blues_

_Tailed Blue_ (_Everes comyntas_ or _Lycaena comyntas_). Wing expanse 1 inch or less. A slender tail projecting from each hind wing. Upper wing surface of varying tones of blue, the males lighter than the females. Lower wing surface grayish white with scattered spots.

_Scudder's Blue_ (_Rusticus scudderi_ or _Lycaena scudderi_). Wing expanse 1 inch or less. No tails on hind wings. Eyes without hairs.

Upper wing surface blue; female has dusky margins on front wings and an orange border with blackish spots near outer margin of the hind wings. Lower wing surface bluish gray with many small spots.

_Silvery Blue_ (_Nomiades lygdamus_ or _Lycaena lygdamus_). Wing expanse 1 inch. No tails on hind wings. Eyes hairy. Upper wing surface silvery blue with dusky margins which are broader in the female. Lower wing surface ashy gray with many darker spots.

_Spring Azure_ (_Cyaniris ladon_ or _Lycaena ladon_). Wing expanse 1 inch. No tails on hind wings. Eyes hairy. Upper wing surface azure blue with black border markings varying greatly, more p.r.o.nounced in the female. Lower wing surface slaty brown with many darker spots.

PART III

THE SKIPPER b.u.t.tERFLIES

SUPERFAMILY _Hesperioidea_

The true b.u.t.terflies 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 b.u.t.terflies, and Hesperioidea, the Skipper b.u.t.terflies. The latter includes these two families:

The Giant Skippers (_Megathymidae_).

The Common Skippers (_Hesperiidae_).

These insects as a whole are distinguished from the higher b.u.t.terflies 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 coc.o.o.ns 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

FAMILY _Megathymidae_

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.

[Ill.u.s.tration: Megathymus yuccae. Female. (After Riley.)]

So far as the story of its life is concerned, the best-known species is the Yucca-borer Skipper (_Megathymus yuccae_) 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

FAMILY _Hesperiidae_

The Skippers are the least developed of the b.u.t.terflies. They show their close relations.h.i.+p to the moths both by their structure and their habits. The larvae make slight coc.o.o.ns before changing to chrysalids, and these chrysalids are so rounded that they suggest the pupae of moths rather than those of b.u.t.terflies. The common name--Skippers--is due to the habit of the b.u.t.terflies--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 b.u.t.terflies, 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 b.u.t.terflies 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 palpus 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 s.e.xes. The colors are chiefly various tones 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 coc.o.o.n when it is ready to change to a chrysalis.

The Skippers found in eastern North America are commonly 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.

THE TRIBE OF THE LARGER SKIPPERS

The b.u.t.terflies of this tribe have that part of the club of the antenna, which is recurved, about as long as the thicker part below it. As a rule, the abdomen is distinctly shorter than the hind wings.

The caterpillars are rather short and thick, and the upper part of the head, when looked at from in front, is square or roundish rather than tapering. The chrysalids have the tongue case attached throughout its length and stopping short of the tips of the wing cases.

=The Silver-spotted Skipper= _Epargyreus t.i.tyrus_

One can seldom draw hard and fast artificial lines in nature. There are all sorts of intermediate conditions which disturb arbitrary cla.s.sifications. It might seem simple enough to say that some insects are leaf-rollers and others are tent-makers, but as a matter of fact in the case of the Silver-spotted Skipper we have an insect which starts its larval life as a leaf-roller and finishes it as a tent-maker. Its life-history is rather interesting and easily observed, if one can find the larvae at work upon the leaves of locusts and other trees. (_See plates, pages 272-273._)

The Silver-spotted Skipper is one of the largest b.u.t.terflies of the interesting group to which it belongs. It lays its eggs upon the upper surface of the leaflets of locusts and other plants of the legume family. In less than a week each egg hatches into a little caterpillar with a very large head and a comparatively large body, tapering rapidly toward the hind end. This little creature cuts out from one side of the leaf a small round flap which it turns over and binds in place by silken threads to make a home for itself. This little home shows considerable variation in its construction but it usually has an arched dome held in place by strands of silk running from the eaten fragment to the surface of the leaf. It remains an occupant of this home until after the second moult. About this time it becomes too large for its house and deserts it to make a new one generally by fastening together two adjacent leaves. These are attached along the edges by silken strands in such a way as to give considerable room.

It leaves one end open as a door out of which the caterpillar crawls to feed at night upon near-by leaves, returning to the house for shelter during the day. They continue to use this habitation until they are full grown as caterpillars and sometimes they change to chrysalids within it. More commonly, however, they crawl away both from the leafy case and the tree that bears it and find such shelter as they can upon the ground near by. Here they spin slight silken coc.o.o.ns within which they change to chrysalids. In the more Northern states there is but one brood a year, so these chrysalids remain in position until early the following summer when they come forth as b.u.t.terflies. Farther south there are two broods each summer, the second brood of b.u.t.terflies appearing chiefly in August.

The Silver-spotted Skipper derives its name from the distinct silvery spots upon the under-wing surface against a background of dark brown.