62 INSECTS AFFECTING DOMESTIC ANIMALS. 
obtained in 1861 from larv:e, which, suspecting them to be carnivorous from the 
very varied stations in which they had occurred, I had supplied with a number of 
fresh-water mollusks, but the habits of which, in consequence of having been away 
from home, I was unable to watch. On September 22, 1863, I found a nearly full- 
grown larva among floating rejectamenta, and between that date and December 23 
he had devoured the mollusks of eleven univalves (genus Planorbis) from one-half 
to three-fourths of an inch in diameter; and on three separate occasions I have seen 
him work his way into the shell. In this operation his pseudopods were energet- 
ically employed, and I found, on cracking the shells after he had withdrawn, that a 
small portion of the tail end of the animal was left untouched—no doubt in conse- 
quence of his being unable to penetrate the small end of the whorl of the shell—and 
also the skin of the remaining part and the horny-tongued membrane. 
My larva transformed to pupa within the ground during the fore part of July; it 
remained in this state but a few days and the fly issued July 13, and soon made its 
presence known by its loud buzzing inside the jar. It was a perfect specimen, and the 
pupal integument was sufficiently firm and polished, that by carefully washing off 
the earth an excellent cabinet specimen was obtained, which retained almost the exact 
form and appearance of the living pupa. Before the escape of the fly, which was 
effected through a longitudinal fissure on the back of the head and thorax, remind- 
ing one of the mode of escape of our harvest-flies (Cicadie), this pupa by means of the 
horns with which it is furnished had pushed itself up to the surface of the earth. 
The pupa (fig. 22, b) is nearly an inch and a quarter in length and a 
third of an inch in diameter. It is cylindrical, slightly curved, as in 
the figure, rounded at the head and tapering at the extreme hind por- 
tion. The abdominal segments are all but the first one provided with 
a ring of fine yellowish bristles, pointed 
backward. There is a stout thorn at the 
anal extremity, bearing six other thorns. 
The pupa state lasts but a few days 
and before the emergence of the fly it is 
pushed to the surface of the ground by 
means of the bristles and thorns of the 
abdomen, with bending movements of 
the body. 
It splits along the dorsal line and the 
fly emerges leaving the pupa case in very 
perfect condition. 
The adult fly (fig. 22, c¢) is an inch or 
ea Tabinas ciratugana mole i length, black throughout, the 
single egg containing parasite (from back of the abdomen covered with a 
BEM): bluish white bloom and the wings smoky 
black. They are common through the summer months and it is pos- 
sible from the different times that full-grown larvie have been observed 
that there is more than a single brood in a year. It seems probable, 
however, that the winter is spent in the larval stage and that the full- 
erown larve observed by Mr. Walsh in September were simply late 
specimens that had lived over the previous winter and would have 
pupated the same fall, producing the flies a few days later, and these 
have laid eggs to pass the succeeding winter. Hart says the larve 
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