GRASSHOPPER'S COUSINS
wing on top and use the file of this wing and the scraper of the left, just the reverse of the custom among the katvdids. "lahe front wings of male crickets are usually very broad and have the outer edges turned down in a wide flap that folds over the sides of the body when the wings are closed. The wings of the females are simpler and usually smaller. The differences between the front wings in the male and the female of one of the tree crickets (Fig. 37) is shown at B and D of Figure 33. The inner half of the wing (or the rear half when the wing is extended) is very large in the male (D) and has only a few veins, which brace or stiffen the wide membranous vibratory area or t_vmpanl?m. The inner basal part, or a,lal area, of the male wing is also larger than in the female and contains a prominent rein (CI«?_) which lnakes a sharp curve toward the edge of the wing. This rein has the stridulating file on its under sur- face. The veins in the wing of an adult female (B) are comparatively simple, and those of a young female (A) are more so. But the complicated venation of the male wing has been de- veloped from the simple type of the female, which is that common to in- sects in general. The wing of a young male (C) is not so different from that of a young female (A) but that the cor- responding veins can be identified, as shown by the lettering. Taking next the wing of the adult male (D), it is an easy matter to determine which veins Fro.a4. A rnole cricket, have been distorted to produce the N««?rtitta a,?*Z*«t?t* stridulating apparatus. When the tree crickets sing they elevate the wings above the back like two broad fans (?igs. 37, 4 °) and move them sidewise so that the file of the right rubs over the scraper of the left.
[57]
INSECTS
