68 



MISC. PUBLICATION 631, U. S. DEPT. OF AGRICULTURE 



2. Larger larvae (up to 16 mm.) ; peritreme forked at its opening, which 



is very- narrow (tig. 32) _». 3 



Smaller larvae (up to 11 mm.) ; peritreme not forked at the opening, 

 which is wide MicrocalUpJiora varipes (Macquart) 



Figure 28. — Chrysomya bezziana, head 

 of female, front view. 



Figure 29. — Chrysomya megacephala, 

 head of female, front view. 



Figure 30. — Chrysomya bezziana, Figure 31. — Chrysomya megacephala, 



head of male, front view. head of male, front view. 



3. Australian and Oriental species ruff fades (Macquart) 



Palaearctic and Ethiopian, more rarely Oriental, species 



albiceps (Wiedemann) 



4. Larvae creamy yellow ; belts of spines strongly developed, the spines 



recurved (fig. 35) ; anterior spiracles with 4 to 6, usually 5, fingerlike 



processes bezziana Villeneuve 



Larvae whitish to yellow ; belts of spines at most moderately developed ; 

 anterior spiracles with 10 to 13 fingerlike processes 5 



5. Larvae yellow ; posterior spiracles closely approximate, separated by 



about one-fifth the diameter of a spiracle (fig. 33) 



chloropyga (Wiedemann) 

 Larvae whitish ; posterior spiracles more remote from each other, sepa- 

 rated by one-third to one-half the diameter of a spiracle. 



marginalis (Wiedemann) 

 megacephala (Fabricius) 



