INSECT FAUNA OF HUMAN EXCREMENT 59I 



wounds and is indirectly the cause of blood poisoning. This 

 species is shown at Plate xxxi, fig. i. 



Oscinis carbonaria Loew. 

 The larvae of the insects of this genus usually attack living 

 plants not previously injured by insects, but a few species live in 

 the deserted burrows of other insects. O. carbonaria was cap- 

 tured several times upon deposits at Washington (May 12, 13, 

 16 and 18) and at Snickers Gap, Virginia (July 18). It is an 

 American species as in fact are all of the following species of 

 this genus, O. -palli^es occurring also in Cuba. 



Oscinis coxendix Fitch. 

 This species, previously bred by Mr. Chittenden from the 

 roots of Ambrosia artemisicefolia at Washington, District of 

 Columbia, was captured also at Washington on human faeces. 



Oscinis ^alli^es Loew. 

 This species was captured September 17 on human excre- 

 ment at Marshall Hall, Maryland. 



Oscinis trigra7nnia Loew. 

 This species was also captured on September 17 at Marshall 

 Hall, Maryland, upon fseces and was bred September 5 from 

 a deposit collected in Washington August 18 and which at that 

 date was apparently about a week old. 



Elachiptera cosiata Loew. 

 The larvae of the insects of this genus attack living plants 

 and decaying vegetation. Specimens have been reared at this 

 office from plants of fall wheat received from F. M. Webster, 

 at Lafayette, Ind. In the present series specimens were cap- 

 tured at Washington upon fresh excrement on May 12 and 13. 



Family AGROMYZID^. 



This family is closely related to the Oscinidae and it has prac- 

 tically the same habits. The larvge of one genus prey upon 

 living plant lice and scale insects but the others feed upon living 



