THE FLIES THAT CAUSE MYIASIS IN MAN 



111 



in about 3 to 7 days ; the route of the larva through the host is not defi- 

 nitely known, but it apparently does not have a lodging stage in the 

 esophagus, as does H. lineatum. 



In man parasitism by this species is not significantly different in its 

 clinical aspects from that of other members of the genus. Numerous 

 cases are on record from northern North America and northern Europe. 



Literature. — Bishopp and coworkers (18) ; Patton (107). 



HYPODERMA LINEATUM (Villers) 



The Common Cattle Grub ; the Heel Fly 

 (Fig. 58) 



Synonym. — Lithohypoderma lineatum i Villers) of Townsend. 



Recognition Characters. — Adult: This species is also beelike in appearance 

 but is less robust and hairy than H. bovis and does not have so strongly the 



Figure 58. — Hypoderma lineatum, adult female. 



aspect of a bumblebee. The mesonotum is covered lightly with pale hairs which 

 may not be noticeable to the naked eye except from a front view; the thorax 

 bears four polished stripes which are briefly interrupted at the suture; these 

 stripes stand out more prominently than they do in H. bovis. The abdominal pile 

 is grayish yellow at the base, brownish to black in the middle, and bright orange 

 at the apex. The femora are dark brown to black, the tibiae and tarsi light 

 brown. Length about 12 mm. Larva (figs. 56, B and 57, B) : Sufficiently character- 

 ized in the key. 



Geographical Distribution. — Nearctic Region: Canada (Quebec, Ontario, 

 Manitoba, Saskatchewan, Alberta, British Columbia), United States (recorded 

 from every State and the District of Columbia). Neotropical Region: Santo 

 Domingo, Puerto Rico (introduced many times, but not established). Palaearctic 



