1924 ] 
The Biology of Trichopoda pennipes Fah. 
69 
rasping mouth parts (mh) and a pair of black anal stigmata, (ans) 
It is quite robust, and although its greatest circumference is 
about midway of its length, it can hardly be called fusiform, 
since it tapers away to a point in front, while the anal end is 
blunt. It is about 10 mm. long by 3.5 mm. in diameter, a sur- 
prising size when one considers that the adult host measures 
but 15 mm. in length. 
The structure of the cephalo-pharnygeal skeleton, and the 
arrangement of the slits in the anal stigmata vary in the dif- 
ferent species, and figures of these organs are therefore included 
in the plates. No sign of the parastomal sclerites mentioned 
by Banks (1912) as occurring in certain muscoid larvse could be 
found in the cephalo-pharyngeal skeleton of T. pennipes. 
PUPARIUM. PI. Ill, figs. 19, 20, 21. 
The pupa itself has not been observed. The puparium 
which encloses it, however, is of a deep reddish-black color, 
cylindrical in shape, and rounded at both ends. It is formed 
from the skin of the mature larva, and upon it the anal stigmata 
appear as twin tubercles at the posterior end. The puparia 
average about 7.5 mm. in length and 3.5 mm. in diameter. At 
the anterior end, before the emergence of the adult fiy, a trans- 
verse split occurs, reaching backward nearly a quarter of the 
length of the puparium. The split then extends around the 
circumference, this resulting in the formation of two flaps which 
are pushed aside by the ptilinum of the emerging adult. 
Some time after the examinations of the puparium had been 
finished by the writer, the work of Greene (1922) on the puparia 
of muscoid flies came to hand. The puparium of T. pennipes 
is there figured and discussed, and significant characters com- 
pared with those of the puparia of other species. 
BIBLIOGRAPHY. 
Aldrich, J. M. 
1905. A catalogue of North American Diptera. Smith- 
sonian Misc. Coll., vol. 16, no. 1444, p. 425. 
1915. Collecting in Tachinidse. Ann. Ent. Soc. America, 
vol. 8, p. 83. (Distribution of T. pennipes.) 
