The Two-winged Flies 



347 



recognize some twenty distinct subfamilies (or families, if the group 

 Muscidae be looked on as a super-family) of these small flies, but the distinc- 

 tions are quite too fine for the general collector to handle. I shall therefore 

 simply refer briefly to a few of the more interesting or abundant or economi- 

 cally important species in this group. 



Fig. 493. — Red-tailed Tachina-fly, Wiiithemia ^-pustulula, a parasite of the army-worm, 

 Leucaiiia unipicncta. a, fly, natural size; b, fly, enlarged; c, army-worm, natural 

 size, upon which eggs have been laid; d, parasitized army-worms, enlarged. (After 

 Slingerland.) 



Of interest because of the extraordinary condition of their eyes are the 

 blackish flies called Diopsidas, which have the eyes on conspicuous elon- 

 gate lateral processes of the head. These eye-stalks bear also the antenna». 

 Only a single species, Sphyraccphala hrevicornis , has been found in this 

 country, and regarding its life-history nothing is known. The flies are to be 

 looked for in woodsy places, and particularly on the leaves of .skunk-cabbage. 



In the water and cast up in masses along the shores of Mono Lake and 

 certain other similar brackish-water lakes in the desert land just east of 

 the Sierra Nevada Mountains in California may be found, at certain seasons 

 of the year, innumerable larv;c of a small predaceous fly of the genus Ephydra. 

 These dead-sea waters support hardly any other animal life, but this fly 

 finds the water much to its liking and breeds there with extraordinary fecun- 

 dity. The Pai Ute Indians of this region, who, like the flies, have a ques- 

 tionable palate, gather these larvae by the bushel, dry them in the sun, and 

 use them for food under the name koo-chah-bee. Prof. Brewer of Yale, 

 who made a trial of koo-chah-bee, savs "it does not taste badl\-, and if one 



