Fig. 58.—Hymenoptera. Lasius interjectus, a harmless winged ant, the yellow ant, with which the winged termite is often confused: A, queen with wings spread, many times natural size; B, worker ant, natural size; C, queen, approximately natural size, with wings partially closed and as usually seen. Ant has a narrower waist and shorter wings than termite. Actual length of queen about 0.3 inch.
Fig. 59.—Hymenoptera. A parasitic wasp, Opius, sp. Actual length 0.1 inch. (Drawing from U. S. D. A.)
Fig. 60.—Mecoptera. Panorpa chelata, one of about 15 Illinois species of scorpionflies. Only the male has the “scorpion” tail. Actual length of insect about 0.5 inch.
Trichoptera
Caddisflies
Insects with two pairs of wings, poorly developed mouthparts of the chewing type, and long antennae; without tails on the posterior end of the body. In repose, the wings are held rooflike over the body and have only a moderate number of longitudinal veins, which are not connected by crossveins into any resemblance of a network. Neither body nor wings are covered with scales. The larvae are wormlike and they live in streams, ponds, and lakes. Many of them build cases of sticks, stones, or sand and move about with only the front end of the body protruding from the case. When disturbed, the larvae withdraw completely into the cases and are then very difficult to see. The adult fly and larva of Rhyacophila fenestra Ross illustrate this order, figs. [61] and [62]. In many aquatic situations, caddisflies are the predominant small animal life and are an important factor in fish food economy. Also, they are stream pollution indicators.
Fig. 61.—Trichoptera. Rhyacophila fenestra; the adult form of this caddisfly is shown here. Actual length about 0.4 inch.