DIPTERA OE MINNESOTA. 



125 



The family is world-wide in its distribution. 



The following Minnesota species are in our collection: /hiflwjiiyia 

 radiciDii. Linn.; Caricca nana, Zett. ; Dialyta, sp. ; Homalomyia cani- 

 cularis. Linn. ; H. incisurata, Zett. ; H. sp. ; Hylemya lipsia, Walk. ; 

 Hyctodesia proxima, Wulp. ; Phorbia hrassicae, Bouche ; P. fusciceps, 

 Zett.; Pcgomyia, 5p. ; Spilogaster nitens, Stein.; Ophyra leucostoma, 

 Wied. ; Hylcphila, sp. 



OESTRTDAE. 



"Bot Flies," "Gad Flies" or "Breeze Flies." 



This is one of the most important families from an economic stand- 

 point. The flies are medium size, some quite large ; without exception 

 the larvae live in or upon quadrupeds, such as horses, cows, sheep, 

 rabbits and gophers. Some few are known to attack man. The bot 

 fly which attacks sheep, places its living young in the nasal passages. 



The adults, like the horse fly, are fond of sunny localities, and in 

 this stage take little or no food. 



Fig. 120. Horse Bot Fly, male; abdomen of female on left, egg on right; enlarged. Lugger 



One of the most interesting and injurious is the Horse Rot Fly, 

 Gastrophilus eqiii. Clark (see Colored Plate I, Fig. lo). The female 

 horse bot fly lays from 400 to 500 eggs, all of which may be placed, 

 under favorable circumstances, upon one horse. These eggs are fast- 

 ened to the hairs, generally of the fore legs, shoulders or chest. A 

 horse instinctively fears this pest, and it will be seen, if in the pasture, 



