90 THE HOUSE FLY— DISEASE CARRIER 



puparia of Musca donicstica in January, 191 1, in order 

 to ascertain what proportion of the pupae were Hving, 

 was surprised when a fully formed and active adult 

 black Spalangia crawled immediately from the opening 

 made by his dissecting needle. This will be described 

 by Girault as Spalangia musccc. A certain proportion 

 of the house fly puparia are affected by this parasite in 

 precisely the same way as are the puparia in Europe 

 by Spalangia niger as described by Bouche. Mr. San- 

 ford's observation shows that the adults may be fully 

 formed and ready to emerge at a very early date. 



Another European Pteromalid parasite, namely, Ste- 

 nomalus mnscarmn, is recorded as being a parasite of 

 the house fly pupa. 



Much attention has been given to the Chalcidoid 

 parasites of the typhoid fly by A. A. Girault and G. E. 

 Sanders, of the University of Illinois. In their first 

 paper {Psyche, December, 1909, pp. 1 19-132) they 

 described an interesting form under the name Nasonia 

 hrevicornis from a series of 640 specimens, nearly all 

 reared from puparia of various flies in the Oflice of the 

 State Entomologist of Illinois at Urbana during 1908. 

 They came from various decomposing materials, from 

 which several species of flies were reared, but a num- 

 ber undoubtedly came from Musca domestica. 



It is a minute, dark, metallic, brassy-green fly with 

 clear wings and rather stolid and serious temperament. 

 Girault and Sanders state that it heeds external influ- 

 ences very slightly, and quietly and persistently gives 

 its whole attention to reproduction. They found that 



