412 



NORTH AMERICAN DIPTERA 



trate the skin. The maggots remain in the host for from forty-five to 

 fifty-five days and cause rather severe muscular pains as well as induc- 

 ing drowsiness. It is said that the adult flies lurk in the vicinity of 

 mosquito infested pools and capture the mosquitoes as they emerge, 

 laying from ten to thirty eggs on each. I have seen mosquitoes heavily 

 laden with the eggs. Ticks and species of Muscidse are also carriers. 



KEY TO GENERA 



1. No facial carina; antennje elongate, the third segment three times as 



long as wide 2 



Facial cai'ina developed, though low; antennje short, the second segment 

 rarely over twice as long as wide 3 



2. Arista rather thickly long plumose Pseudogametes Bischof 



Arista with rays on upper side only (1, 2, 4) Dermatobia Brauer 



3. Arista bare (South America) Rogenhofera Brauer 



Arista pectinate above and usually with one or more rays below on the 



apical part (3, 5, 6) *Cuterebra Clark 



* I can find no character by which to separate Bogeria Austen, described from a damaged 

 specimen lacking the aristal rays and based upon the bare arista. Townsend (Ins. Ins. Mens., 

 V, p. 23) attempts to separate the two genera on the shape of the facial depression but I cannot 

 follow him in this. 



Cuterebrida;. — 1, Dermatobia cyaniventris; 2, Dermatobia; 3, Cuterebra, antennse ; 4, 

 Dermatobia, tarsus ; 5, Cuterebra, tarsus ; 6, Cuterebra. 



