Fig. 140. a, Wasp. b, Bee. Note these have four wings.
Fig. 141. The Red Admiral butterfly. Note the knobbed antennæ.
Flies.—These have only two wings, usually transparent. Behind each of these wings a short thread with a knob on it extends out on each side of the body instead of hind wings, [Fig. 139]. House-flies, horse-flies and mosquitoes are examples of flies.
Bees, Wasps and Ants.—Bees, wasps and the winged form of ants have four transparent wings, [Fig. 140]. Some flies resemble bees and wasps, but if examined it will be found that they have only two wings instead of four.
Fig. 142. The Cabbage butterfly.
