ORTHOPTERA 47 



4. The sound-producing apparatus of the male: again 

 it is a file and scraper; but in this group both are on each 

 fore wing. The file is on the under side of one of the 

 thickened basal veins, and the scraper is on the hind 

 margin near the base. In "singing" the fore wings are 

 lifted and rubbed together, the file of either one being 

 drawn like a violin bow across the scraper of the other. 

 Adjacent to the file the wing veins take a circuitous 

 course to inclose a wide, disclike vibrating ("sounding 

 board") area. Thus the venation of the male fore wing 

 has come to differ from that of the female. 



III. Crickets. 



1. With a common black field cricket in hand compare 



part by part with the preceding, noting in addition 



especially : 



(a) The polished and shining surfaces of the body that 

 facilitate escaping through tangles of rubbish and 

 weeds. Crickets are "slippery." 



(b) The shorter, more cylindric, prothorax. 



(c) The two long tails. 



(d) The long, slender, cylindric ovipositor of the 

 female, by means of which the eggs are laid singly, 

 deep in the soil. 



(e) The sound-producing apparatus of the male, 

 similar in type to that of the long-horn grasshopper 

 but more highly developed. 



