“No order surpasses this in the number of species or in the immense swarms of individuals belonging to the same species which are frequently met with. The wings, which are variously veined, though appearing naked to the unaided eye, are often thickly covered with very minute hairs or hooks. As an order the Diptera are decidedly injurious to man, whether we consider the annoyances to ourselves or our animals of the Mosquito, Buffalo-gnat, Gad-fly, Breeze-fly, Zimb or Stomoxys, or the injury to our crops of the Hessian-fly, Wheat-midge, Cabbage-maggot, Onion-maggot, etc. There are, in fact, but two families, Syrphidæ and Tachinidæ, which can be looked upon as beneficial to the cultivator, though many act the part of scavengers. No insects, not even the Lepidoptera, furnish such a variety of curious larval characters, and none, perhaps, offer a wider or more interesting field of investigation to the biologist. It is difficult to give any very satisfactory arrangement of these Two-winged flies, though they easily fall into two rather artificial sections. These are: 1st, Nemocera, or those with long antennæ, having more than six joints, and palpi having four or five joints. The pupa is naked, as in the Lepidoptera, with the limbs exposed. This kind of pupa is called obtected. 2d, Brachocera, or those with short antennæ, not having more than three distinct joints, and palpi with one or two joints. The pupa is mostly coarctate, i. e., is formed within, and more or less completely connected with, the hardened and shrunken skin of the larva.
Fig. 26.—The Sheep Bot (Œstrus ovis). 1, 2, flies;
3, puparium; 4, 5, and 6, larvæ or bots.
“The most anomalous of the Diptera are the Forest-flies and Sheep-ticks (Hippoboscidæ). They have a horny and flattened body, and resemble lice in their parasitic habits, living beneath the hair of bats and birds. Their mode of development has always attracted the attention of entomologists. The larvæ are hatched in the abdomen of the female, which is capable of distention. There it remains and, after assuming the pupa state, is deposited in the form of a short, white, egg-like object, without trace of articulation, and nearly as large as the abdomen of the female fly. Closely allied to these are the Bat-ticks (Nycteribidæ), which possess neither wings nor balancers, and remind one strongly of spiders.
“In this order we may also place certain wingless lice (such as Braula cœca, Nitzch), which infests the Honey-bee in Europe, northern Africa, and western Asia, but which has not yet been detected in this country.
Fig. 27.—A Flea (Pulex). (From Packard.)
“Suborder [Aphaniptera] (αϕανης, inconspicuous; πτερον, wing) or Fleas, comprising the single family Pulicidæ, now placed with the Diptera. Everybody is supposed to be familiar with the appearance of the Flea—its bloodthirsty propensities and amazing muscular power; and while everyone may not have the leisure and means to experience the exhilarating influence of the chase after larger animals, there is no one—be he never so humble—who may not indulge in the hunt after this smaller game! In place of wings the flea has four small, scaly plates. The minute eggs—about a dozen to each female—are laid in obscure places, such as the cracks of a floor, the hair of rugs, etc., and the larva is worm-like and feeds upon whatever animal matter—as grease and blood—or decaying vegetable matter it can find.
“Order [ORTHOPTERA] (ορθος, straight; πτερον, wing), or Straight-winged Insects. Characterized by having the front wings (called tegmina) straight and usually narrow, pergameneous or parchment-like, thickly veined, and overlapping at tips when closed; the hind wings large and folding longitudinally like a fan. Transformations incomplete.
