FIRST LESSONS IN ZOOLOGY 



closel)' relatcil to the kat\'dids, although differing much 

 from them in appearance. They are black, and live in 

 holes in the ground or in concealed places in houses, coming 

 out at night to hunt for food and to " sing." The eggs 

 are laid in autumn and are hatched the following spring. 

 Obtain some crickets and distinguish the males from 

 the female. The female has a long pointed ovipositor 

 (egg-laying organ) lacking in the males, while the bases 

 of the fore wings of the male are peculiarly modified. 

 E.xamine carefully these modified 

 parts. Under the microscope the 

 principal vein, which extends di- 

 agonally across the base of the 

 wing, will be seen to be furnished 

 with transverse ridges like a file 

 (fig, 139). On the inner margin 

 of the wing, a short distance from 

 the base toward the end of the 

 principal vein, is a hardened por- 

 tion \\hich may be called the 

 I'iG. 130.— Cricket and file scraper. Each fore wing is there- 



(part of llie s<.uiid-making . . ^ 



apparatus). (Cricket natif- fore provided With a file and 

 ral size; the file i;ie,.tlv gcraper. When the Cricket wishcs 



magnified; from speci.nev.-.i , , • ,1 , , ^ 1 • 



to make his call he elevates his 

 fore wings at an angle of about forty-five degrees with 

 the bod\-; then holding them in sucli a position that the 

 scraper of one rests on the file of the other, he moves 

 them back and forth laterall)', so that the two parts rasp 

 upon each other. This throws the wing membranes into 

 vibration and produces the call. 



The solitary bees and the digger-wasps. — The soli- 

 tary bees are so called because of their manner of living 

 apart and not in communities as do the social bees, like 

 the bumble- and honey-bee. Among them there are no 

 ncLiter-worker individuals, each female making a nest for 



