1913] Pinkus — History an I HaMts of Spalangia Muscidarum 149 



near the stable. When the straw began to decay stable flies 

 visited it in large numbers, depositing thousands of eggs. In ad- 

 dition to the stable fly, a number of other species were found to 

 be breeding in this rotting straw, such as Phoridse, Chironomidae 

 and Anthomyidae. No house flies {Musca domestica Linn.) or any 

 other species of flies which commonly breed in dung were found 

 although Musca domestica was present in the vicinity in consider- 

 able numbers. In a few weeks great numbers of Stomoxys larva? 

 of various sizes, as well as pupa?, were found in the straw. At this 

 time a screened cage was placed over the pan in order to collect 

 the flies as they emerged. Numbers of flies appeared daily for 

 some time but the number was observed to diminish noticeably 

 later. Upon examination of the straw the majority of the Sto- 

 moxys pupae were found rather dark in color, some being almost 

 black. When the cephalic ends of these pupae were broken off 

 in some cases the pupae of parasites were found to be contained 

 within, and in others the adult parasites came out as soon as 

 the pupae were broken. Considerable numbers of the Stomoxys 

 pupae were dead but no parasites were found within them. These 

 pupae were in the form of a soft, whitish, malodorous mass. The 

 death of these pupae appeared to be due, in part at least, to the par- 

 asites, as will be explained later. 



Spalangia muscidarum Richardson appears to have a wide 

 distribution. It has been bred from the house fly by Mr. C. H. 

 Richardson, Jr., near Boston, Mass., as well as by Doctor L. O. 

 Howard at Washington, D. C, from the same host. During this 

 investigation, adults emerged on October 7, 1912, from Stomoxys 

 pupae collected by Mr. F. C. Bishopp at Gainesville, Texas on 

 September 6, 1912. Other adults began emerging on October 

 26, 1912, from puparia collected by F. C. Bishopp and E. O. G. 

 Kelly at Wellington, Kansas, on September 21, 1912, and others 

 appeared on January 15, 1913 from puparia collected October 

 25, 1912 by F. C. Bishopp at Addis, Louisiana. Numbers have 

 also been bred from pupae collected at Denison, Texas, December 

 6, 1912. As has been pointed out, the parasite is undoubtedly 

 very common in the vicinity of Dallas, Texas. 



At Dallas the breeding was conducted both in the laboratory 

 and out of doors. In the latter situation some adults emerged at 



