08 
the maggots force their way through the skin of their host and 
drop to the ground. Here they burrow in the earth, and, con- 
tracting into brown barrel-shaped puparia, they rest for awhile. 
Inside this puparium, composed of the old larval skin, the 
true pupa is formed, and later the winged fly, which breaks 
through the surrounding skins and crawls towards the light of 
day. In avery short time it is able to use its wings, and is 
ready to enjoy life after its own fashion. A locust harboring 
such a maggot, or several of them, is less active than others, 
and seems to look upon life as a rather serious affair, in fact to 
think it a real bore. Fishermen in search of bait catch such 
languid locusts much more readily than healthy ones, but find, 
in pulling away their wings or heads, a humane way that disci- 
ples of Isaac Walton have, nothing but an almost empty shell, 
by no means a tempting morsel for a fish. Several species of 
Tachina-flies infest locusts. 
Flesh-fly (Sarcophaga carnaria Linn. ), a well known scaven- 
ger in Kurope, Australia and America, is also found as a true 
parasite in many species of locusts. It, as well as its earlier 
stages, are illustrated in fig. 19. This illustration will also 
show the shape, size and general appearance of a true tachi- 
na-fly, which is quite similar to it. 
Bee-Fly— (Systechus oreas ).—During the autumn of 1895 
many fields, meadows and pastures were inspected to find eggs 
of the migratory species of locusts, and invariably the larvee 
of this fly were found in large numbers, showing that this 
friend of the farmeris doing good work. The adult fly is illus 
t im i ‘tl 
Hf wei 

‘ 
Fig. 34.—Systoeechus oreas.—Femule fly. (After Riley.) 
