306 Annals Entomological Society of America [Vol. VII, 
The muscles and fat cells are conspicuous, but do not differ 
particularly from those of other dipterous forms. 
I limit my description of the anatomy to the fewest words 
possible, as the figures and plates tell the story sufficiently. The 
interesting thing about the anatomy of the larva is that it is so 
little different from that of any free-living, outside-feeding dip- 
terous larva of Muscid type. Either the parasitic habit makes no 
less demands on alimentary canal, respiratory, circulatory and 
secretory systems than the free life habits, or this insect has so 
recently adopted a parasitic habit that no considerable struc- 
tural changes in its organs have yet been brought about in 
connection with it. 
This paper was prepared in the Entomological Laboratory 
of Stanford University. 
