Directions for Collecting and Preserving Insects. Charles V. Riley
of the second either feeding externally on leaves or inclosed in galls. They are at once distinguished from the other Hymenoptera by the larvæ having true legs, which, however, in the case of the Horn-tails, are very small and exarticulate. The larvæ of many Saw-flies have, besides, prolegs, which are, however, always distinguishable from those of Lepidopterous larvæ by being more numerous and by having no hooks.
Fig. 9.—A Chafer,
Cotalpa lanigera. (After Packard.)
“Order COLEOPTERA (κολεος, a sheath; πτερον, wing). Beetles or Shield-winged Insects. Characterized by having four wings, the front pair (called elytra) horny or leathery, and usually united down the back with a straight suture when at rest, the hind ones membranous and folded up under the elytra when at rest. Transformations complete.
Fig. 10.—A Longicorn, Saperda candida. a, larva; b, pupa; c, beetle.
Fig. 11.—The Plum Curculio, Conotrachelus nenuphar. a, larva; b, pupa; c, beetle; d, plum showing egg-puncture and crescent.
Fig. 12.—A Soldier-beetle, Chauliognathus pennsylvanicus. a, larva; b–h, parts of larva enlarged; i, beetle.
“This is an order of great importance, and in the vast number and diversity of the species comprised in it outranks any of the others. The ease with which the insects of this order are obtained and preserved make it one of the most attractive to the amateur, and beetles are, perhaps, of all insects, the best known and understood in the popular mind. For the same reason they have, in the perfect state, received most attention from the entomologists, but their transformations and preparatory forms yet offer a wide and inviting field for the student. The simplest and best-known classification of the beetles is the tarsal system, founded on the number of joints to the tarsi, by which we get four great sections: (1) Pentamera, in which all the tarsi are 5-jointed; (2) Heteromera, with the four anterior 5-jointed and the two posterior 4-jointed; (3) Pseudo-tetramera, with apparently only four joints to all the tarsi, though, in reality, there is a fifth penultimate joint, diminutive and concealed; (4) Pseudo-trimera, with apparently only three joints to all the tarsi. This system, like most others, is not perfect, as there are numerous species not possessing five joints to the tarsi belonging to the first section; and for practical purposes beetles may be very well arranged according to habit. We thus get, first, the Adephaga, or carnivorous species, including all those which prey on other living insects, and to which, following Mr. Walsh, I have, for obvious reasons, applied the suggestive term ‘Cannibal’; second, the Necrophaga, comprising those which feed on carrion, dung, fungi, and decaying vegetation; third, the Phytophaga, embracing all those feeding on living vegetation. This arrangement is by no means perfect, for there are beetles which are carnivorous in the larva and herbivorous in the imago state; while some of the Necrophaga are actually parasitic. Yet, it is not more artificial than others which have been proposed. The carnivorous species, broadly speaking, are Pentamerous, the only striking exception being the Coccinellidæ (Lady-birds), which are Pseudo-trimerous. The carrion-feeders are also Pentamerous; but vegetable-feeders are found in all the tarsal divisions, though the Pseudo-tetramera are the more essentially herbivorous, and consequently the most injurious.”
Fig. 13.—The Bogus Potato-beetle, Doryphora juncta. a, eggs; b, larvæ; c, beetle; d and e, parts of beetle enlarged.
“Order LEPIDOPTERA (λεπις, a scale; πτερον, wing). Butterflies and Moths, or scaly-winged insects. Characterized by having four branching-veined membranous wings, each more or less densely covered on both sides with minute imbricated scales which are attached by a stalk, but which easily rub off, and appear to the unaided eye like minute particles of glistening dust or powder. Transformations complete.
Fig. 14.—A Butterfly,
Pieris oleracea.
Fig. 15.—A Sphingid,
Ampelophaga myron.
“Next to the Lepidoptera, the Coleoptera are, perhaps, most familiar to the popular mind. Every one admires the beauty of these frail creatures, dressed in every conceivable pattern, and adorned with every conceivable color, so as to rival the delicate hues of the rainbow, and eclipse the most fantastic and elaborate designs of man. When magnified, the scales, to which this beauty of pattern and color is entirely due, present all manner of shapes, according to the particular species or the particular part of the individual from which they are taken. According to Lewenhoeck, there are 400,000 of these scales on the wing of the common silkworm.
“The transformations of these insects are complete, and the changes are usually so sudden and striking as to have excited the wonder and admiration of observers from earliest times.
Fig. 16.—A Moth,
Utetheisa bella.
“The more common form of the larva is exampled in the ordinary caterpillar—a cylindrical worm with a head, twelve joints and a sub-joint; six thoracic or true legs, four abdominal and two anal prolegs. But there is a great variety of these larvæ, some having no legs whatever, some having only the jointed legs, and others having either four, six, eight, or ten, but never more than ten prolegs. With few exceptions they are all vegetable-feeders, and with still fewer exceptions, terrestrial. The perfect insects make free use of their ample wings, but walk little; and their legs are weak, and not modified in the various ways so noticeable in other orders, while the front pair in some butterflies are impotent.
“As an order this must be considered the most injurious of the seven.
Fig. 17.—A Clothes-moth (Tinea pellionella)—enlarged. a, adult; b, larva; c, larva in case.
“A convenient system of classification for the Lepidoptera is based on the structure of the antennæ. By it we get two great sections: 1st, Butterflies (Rhopalocera); 2d, Moths (Heterocera), which latter may again be divided into Crepuscular and Nocturnal Moths. Butterflies are at once distinguished from moths by their antennæ being straight, stiff and knobbed, and by being day-fliers or diurnal; while moths have the antennæ tapering to a point, and are, for the most part, night-flyers or nocturnal. The crepuscular moths, composed mostly of the Sphinges or Hawk-moths, hover over flowers at eve, and connect the two sections not only in habit, but in the character of the antennæ which first thicken toward the end, and then suddenly terminate in a point or hook.
Fig. 18.—A Plant-bug
(Euschistus punctipes).
“Order HEMIPTERA (ἡμι, half; πτερον, wing), Bugs. The insects of this order are naturally separated into two great sections; 1st, Half-winged Bugs, or Heteroptera (ἑτερος, different; πτερον, wing) having the basal half of the front wings (called hemelytra) coriaceous