170 INSECT AXD VERTEBRATE ENEMIES 



(1902) in his monograph on the Cynipidae. The members of the 

 genus Figites (fig. 76) are parasitic on dipterous larvae which live 

 in various kinds of excrement, and in consequence the minute 

 adult flies may be caught frequenting human, horse, coav and 

 other kinds of excrement for the purpose of depositing theii' eggs 

 on the dipterous larvae which may be found there. The species 

 most commonly attacked belong to the genera of the dipterous 

 families which have coprophagous larvae, such as the Muscidae, 

 Anthomyidae, Sarcophagidae and Scatophagidae. The commonest 

 species, Figites scutellarius Rossi, has been reared by Forster from 

 M. domestica according to Dalla-ToiTe. Other species Avhich have 

 been reared from M. domestica are F. striolatus and F. antho- 

 inyiarum. Further investigations will no doubt indicate that a 

 number of the species of Figites which have already been de- 

 scribed are able to parasitise M. domestica. 



Predaceous Insects. 



As Howard has pointed out, it is a remarkable fact that the 

 larvae of M. domestica are not destroyed to a greater extent than 

 our observations would appear to indicate by the numerous species 

 of predaceous insects which feed upon soft-bodied insects. To 

 a small extent the gi'ound-beetles (Carabidae) and rove-beetles 

 (Staphylinidae) may sometimes be found feeding or induced to 

 feed upon the larvae of M. domestica, but not to the extent that 

 they are accustomed to feed upon other soft-bodied larvae such as 

 many lepidopterous, coleopterous and other dipterous larvae. 



Packard (1874) records the occurrence of what was probably a 

 Dermestid beetle, which he figures ; this was found by him in a 

 pupa of if. domestica. Berg (1898) states that in South America 

 a species of beetle, Trox suberosus F., locally known as " Champi," 

 is an indirect destructor of the common fly. 



Ants are frequently responsible for the destruction of M. do- 

 mestica in the egg, larval and adult stage. Wheeler (1910) records 

 ants feeding on house-flies and their larvae. He informs me that 

 he has seen the Fire Ant Solenopsis geminata Fab. at Quiragua, 

 Guatemala, feeding upon the larvae of M. domestica which they 

 extracted from human excrement. Howard (1911) refers to the 



