PARASITIC ON ANTS. 431 
The sternal surface has strongly marked depressions 
for the reception of the legs. The coxe of the first pair 
of legs are largely developed, flattened, almost touch in 
the median line, and nearly conceal the mouth, as in the 
typical Uropodas. The genital opening of the male is 
rather large, round, and placed centrally between the 
coxe of the second pair of legs. The female appears 
only to be distinguished from the male by being more 
strongly chitinised, and by the conspicuous valval plate 
which occupies the whole space between the cox of 
the second and third pairs of legs and extends beyond 
both. 
The nymph is less square in the abdomen than the 
adult, and the border of hairs is absent ; the margin is 
somewhat undulated, the concave undulations being so 
placed as to give free action to the legs when raised ; 
the central depression of the abdomen is far less 
marked than in the adult ; a slight ridge runs all round 
the dorsal surface a little withia the margin; four 
ridges, two anterior and two posterior, run from the 
circumscribing ridge to a raised ellipse in the centre ; 
there are not any plates for the protection of the legs, 
and the coxe of the first pair are not flattened as in the 
adult. 
This mite lives in the nests of Formica flava. 
Description of a New Genus and Species of Phoride 
parasitic on Ants. By G. H. Vrrratz, Esq., Memb. 
Entom. Soc. 
Siz Joun Lussocr has kindly forwarded for my exami- 
nation and determination certain specimens of dipterous 
insects said to have been found parasitic on species of 
ants, which latter he has been studying with care as to 
their habits. Having given considerable attention to 
the family Phoride, I was agreeably surprised to find 
