[110] REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 
distinguished from that of Sarcophaga by the obsolescence (or in some species entire 
absence) of the prothoracic spiracles so prominent in Sarcophaga, and the absence of 
a cavity for the anal spiracles, both ends of the body being quite uniformly rounded. 
Barthelemy has described the larva of Senometopia atropivora (Ann. Sc. jVa<.,4 e ser., 
vii, p. 115), while Laboulbene has described both larva and pupa of Tachina villica 
(Ann. Soc. Ent. Fr., 1861, p. 231, pi. 7) ; but as these descriptions are not readily acces- 
sible to the American reader, I reproduce from the Trans. Ac. Sc. St. Louis, vol. iii, p. 
238-239 my description of the larva and pupa of Sarcophaga sarracenioe, and add for 
comparison that of Belvoisia bifasciata (Fab.), one of our largest and most beautiful 
species, parasitic on Citheronia regalis and various species of Dryocampa. 
Sarcophaga sarracenije. Larva.— 0.30-0.85 inch long. Body composed of but 11 
visible joints exclusive of the head; microscopically and transversely shagreened r. 
transversely wrinkled, the hind wrinkle on each joint more particularly prominent 
laterally. Head extremely small, or one-fourth as large as joint 1, showing a division 
into two maxillary lobes at the tip and a larger labial lobe beneath, with a smal) 
bunch of setous fibres issuing from it; the black retractile jaws, of the ordinary form, 
issuing between these lobes, and the antennae showing in two small rufous projections 
above the maxillary lobes, sparsely armed anteriorly with minute conical, sharp- 
pointed spines decurved iD front, directed backward beneath. Prothoracic spiracle 
pale rufous, retractile, sponge-like, studded with numerous lobules, divided at the end 
into a variable number of branches (6 being usually apparent, never more than 8)> 
which in their turn ramify into lobules. Anal stigmatic cavity quite deep ; the fleshy 
prominences on the carina surrounding it, sub-obsolete ; the stigmata but slightly 
excavated below, the border brown, inclosing three brown openings, the lower ends of 
which reach to a circular clear space in the corneous and pale rufous peritreme. Anal 
prologs quite small, with the longitudinal anal slit between, and a corneous plate in 
front of them. 
Puparium. — 0.25-0.50 inch long ; neither smooth nor highly polished, and varying from 
yellowish-brown to deep brown-black in color. Insections more or less distinctly 
traceable. Head and prothoracic joint retracted ; the prothoracic spiracles protrud- 
ing and forming two small ears about as long as joint 2 ; the mass of lobules hardened 
and rufous. Joints 2 and 3 constricted and flattened ; 4 suddenly bulging. End of 
body squarely docked by spiracular cavity, the rim of which forms quite a ridge. 
Belvoisia bifasciata. Larva. — Length 15 mm . White, the skin soft ; body cylin- 
drical, tapering on the anterior joints towards the head, the apex obliquely truncated. 
Head small, furnished with two stout black hooks, situated under two crescentic ele- 
vations at a moderate distance apart ; when viewed from in front the head obscurely 
bilobed, near the center of each lobe two chitinous points, one situated above the other. 
No prothoracic spiracles apparent, a distinct circular spiracle on the posterior border 
of the fourth joint behind the head, and situated slightly above the median line. The 
anterior border of each joint slightly prominent and, except on the dorsal side of the 
apical joints, roughened with minute points, the posterior border of the apical joints 
similarly roughened. Joints 4-11 with a distinct transverse median depression on the 
ventral side, the depression deepest on the intermediate joints, the portion behind this 
depression on the joint 11 forming a prominent transverse tubercle beneath the trunca- 
tion, upon which the anal spiracles are situated. Anal spiracles black, each with the 
slit-like openings, and a circular spot in a clear space beneath them. 
In Westwood's Introduction, vol. ii, fig. 131, is copied from BouchC, a figure of the 
larva of Tachina concinnata of similar form to that of Belvoisia; but the peculiar " pro- 
thoracic spiracle" figured in connection is not apparent in the larva before me. In 
the normal form of theTachinid puparium the anterior pair of spiracular openings are 
even with the general surface of the puparium, so as to be discoverable with difficulty. 
The true spiracles are iuternal, and may be found opposite those perforations on the 
membrane which lines the puparium after the fly has escaped. The puparium is red- 
dish-brown, the anal spiracles and the anus black ; the joint of the body not distinct; 
