304 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



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

 said by Professor Riley to be that — 



The TacMna larva is rounded posteriorly, with a small spiracular oavity, easily 

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

 rounded at each end. The Sarcopha{]a larva is more truncate behind, with fleshy 

 warts on the rim of the spiracular cavity, and ^ith a more tai)ering head ; it contracts* 

 a pupa, which is also truncate behind and more tapering in front, wheie the protho- 

 racic spiracles show, as they never do in TacMna. 



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, tlius partaking of the nature of parasites. 

 Their habits are then similar to the Tachinidae. The larva lives within 

 the insect, and similarly issues when fall grown to pupate under ground. 



During the summer of 1878 several specimens of a flesh-fly were reared 

 from pui)ae of Aletia. These proved to be specimens of Sarcophaga sar- 

 raceniae, Riley, a probable American variety of that widespread scaven- 

 ger Sarcopliaga carnaria (Plate XIII, fig. 6), Linn., a species common to 

 Europe, America, and Australia certainly, and x^i'obably elsewhere to 

 be found.* Sarraxieniae was first described by Professor Riley, in a paper 

 read before the Saint Louis Academy of Sciences, as feeding upon the 

 dead insects to be found in the leaves of Sarracenia. Plate XIV, fig. 1, 

 represents this insect in its various stages. 



Several specimens of sarraceniae have been secured the present sum- 

 mer (1879), and also what may prove to be a new species of SarcopJmga. 



Plate XIV, Fig. 2, represents the insect in aU stages ; a is the egg, 

 natural size; b is the egg enlarged; c is the fidl grown larva; d is the 

 head of the larva enlarged ; e is the puparium ; and / the adult insect. 



Phora aletiae, Comstock.t — August 12, 1879, a large number of 

 small white maggots were found in chrysalides sent from Minters, Ala. 

 These maggots, which appeared nearly full grown, were about 0.15 inch 

 (4'"'") in length ; they were rather slender, the 9th segment being the 

 broadest. The posterior end of the body was large and rounded, and the 

 anterior end tapered gradually to a point. 



Examination with a lens showed that each segment was armed later- 

 ally with four short, stout spines (two on each side), and the i)osterior 

 end of the body was furnished with six. August 16 these larvae com- 

 menced to pupate. The puparium w^as light brown in color, 1""° by 

 2'""' in size. The front side showed the joining of the segments, and 

 was somewhat rugose ; the back side was smooth ; the posterior end 

 was rounded and armed with the same six small spines that were present 

 in the larva ; the anterior end of the body was more i>ointed. From 

 about the third thoracic segment two long black excurved spines pro- 

 truded, which presented the most characteristic feature of the iiuparium. 

 The perfect flies began to issue in great numbers August 27, or about 

 ten days from the time of commencing to pupate. They proved to be 

 active little yellowish-brown two-winged flies, with robust bodies and 

 vshort, stout wings. They are well represented at Plate XIV, Fig. 3, as 

 also are the larva and pupa. 



From present indications, this insect bids fair to be one of the most 

 important, as it is one of the most interesting, of the parasites of the 

 cotton-worm. 



* I am in receipt of a communication from Baron Osten-Sacken, commenting upon 

 the above, in whic^ he says : " Allow me to observe, in this connection, that Surco- 

 phaga carncria does not occur in North America. You will fmd that statement, with 

 some detail, in my recent Catalogue of tb" described Noith American Diptera, p. 158." 



tFor technical description see special report, pp. 209-211. 



