THE FLIES THAT CAUSE MYIASIS IN MAX 131 



The Genus HYDROTAEA Robineau-Desvoidy 



The following characters will merely aid in a recognition of this 

 genus: for a more positive determination it will be best to consult a 

 more comprehensive key to the genera of Anthomyiidae. 



The eyes are contiguous in the males; in the females the front is 

 broad and cruciate frontals are present. In the species considered 

 here, there are two presutural dorsocentrals, two sternopleurals and no 

 hypopleurals ; the hind tibia has only one anterodorsal bristle in addi- 

 tion to the preapical one. Vein m^. runs straight to the margin, the 

 apical cell consequently being broadly open; the second anal vein is of 

 moderate length, not reaching the wing margin ; the third anal is short. 

 In the male the front femur is excavated below near the apex, with a 

 tooth basad of the excavation ( rig. 64 ) . 



Life Histories. — Comparatively little information is available. The 

 larvae live in excrement or in partially decomposed vegetable matter; 

 several species have been reared from birds' nests. The larvae are 

 at first saprophagous. although in the third stage they may become 

 carnivorous and feed on other dipterous larvae. In several species 

 the adults, especially the female-, annoy man and cattle by persist- 

 ently alighting on their bodies in search of sweat or blood drawn by 

 bloodsucking flies. 



Larva. — The larva of only one species. II. J<:ntipe$ (Fabricius). has 

 been described (Keilin 66, p. 399) ; it is of the usual muscoid type. 



HYDROTAEA METEORICA (Linnaeus) 



Recognition Characters. — Adult: This is a black species, about 4 to 6 mm. 

 in length. The thorax is shining in the male, ashy gray in the female; the 

 abdomen is gray pollinose, with a median black band formed from connected 

 triangles. The eyes in the male are narrowly separated. The wings are lightly 

 infumated ; the halteres black. 



Geographical Distribution. — Nearctic Region: Quebec. Alberta. Maine. Ver- 

 mont, Connecticut. New York. Maryland. North Carolina. Indiana. Illinois. North 

 Dakota. South Dakota. Montana, Idaho. Colorado. Now Mexico, Washington, 

 California. Palaearctic Region : Ireland. Scotland. England. France, Nether- 

 lands. Corsica, Sweden. Finland, Germany. Austria. Russ 



Biology and Pathogenesis. — No details of life history are known. 

 Two records of intestinal myiasis have been published; in one a black- 

 smith, after several months of illness, passed a quantity of larvae from 

 which adults were reared; in the other about 60 larvae, said to be this 

 species, were recovered from stools of children suffering from dysen- 

 tery. This species has also been recorded in aural myiasis. 



The Genus PEROMA Robineau-Desvoidy 



There is but one species known in this genus. 



PEROMA ROSTRATA Robineau-Desvoidy 



Recognition Characters. — Adult : This is a Mack fly, about 6-7 mm. in length : 

 the abdomen is metallic bine, the color being especially noticeable from the 

 posterior view; the last abdominal segment is covered with an ashy-gray pollen. 

 The epistoma is strongly produced; the hypopleura bear some strong hairs below 

 and in front of the spiracle. Larva: This is a smooth maggot of the ordinary 

 muscoid type; for the structure of the posterior spiracles, see figure 73. 



Geographical Distribution. — Australian Region: Recorded from every state 

 in Australia but evidently limited to that continent. 



