FLESH-FLIES. 205 



to deposit them within a given time after fertilization they hatch "within 

 her body, and we have the phenomenon of a viviparous insect. The 

 ovaries are large and arranged in a spiral manner, and De Geer is said 

 to vouch for the development of 20,000 larvae in one female. The dis- 

 tinction between the earlier forms of the flesh-flies and Tachina flies is 

 said by Professor Eiley to be that 



The Tachina larva is rounded posteriorly, with a small spiracular cavity, easily 

 closed, and having a smooth rim ; it contracts to a pupa, which is quite uniformly 

 rounded at each end. The Sarcophaga larva is more truncate behind, with fleshy warts 

 on the rim of the spiracular cavity, and with a more tapering head; it contracts to a 

 pupa, which is also truncate behind and more tapering in front, where the prothoracic 

 spiracles show, as they never do in Tachina. 



It is the general habit of the flesh-flies to deposit their eggs or young 

 upon dead and putrefying animal matter, but they are often known to 

 thus infest living animals, thus par-taking of the nature of- parasites. 

 Their habits are then similar to the 

 Tachinidae. The larva lives within the 

 insect, and similarly issues when full 

 grown to pupate under ground. 



During the summer of 1878 several 

 specimens of a flesh-fly were reared 

 from pupae of Aletia. These proved 

 to be specimens of Sarcopliaga sarra- FIG. 47. Sarcophaga camaria var. 

 ceniae Eiley, a probable American vari- sarracenae. 



ety of that widespread scavenger Sarcopliaga carnaria, Linn., a species 

 common to Europe, America, and Australia certainly, and probably else- 

 where to be found. Sarraceniae was first described by Professor Eiley, 

 in a paper read before the Saint Louis Academy of Sciences, as feeding 

 upon the dead insects to be found in the leaves of Sarracenias. Fig. 47 

 represents this insect in its various stages, and the following is Professor 

 Eiley's description of the species : 



Sarcopliaga sarraceniae, n. s. 



LARVA. 0.30-0.85 inch long; body composed of but 11 visible points, exclusive of 

 the head ; microscopically and transversely shagreened ; 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 small bunch of 

 setons fibers 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 in 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 prom- 

 inences on the carina surrounding it subobsolete; 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 peritrevne. Anal pro- 

 legs quite small, with the longitudinal anal slit between and a corneous plate in front 

 of them. 



