208 REPORT UPON COTTON INSECTS. 



parasite is common or not, though from the number of chrysalides de- 

 stroyed by the larvae reared it will prove a very useful one if common. 



Figure 48 represents the insect in all stages j a is the egg, natural 

 size ; 6 is the egg enlarged ; c is the full grown larva ; d is the head of 

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

 PHOBA ALETIAE: 



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 mm ) 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 posterior 

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

 menced to pupate. The puparium was light brown in color, l mm by 

 2 mm 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 pointed. From 

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

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

 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 

 short, stout wings. They are well represented at Fig. 49, as also are 

 the larva and pupa. 



It was at first thought that these larvae would not prove to be truly 

 parasitic, but that they were to be found only in those cotton- worm chrys- 

 alides which were already dead from some other cause and decaying. 

 Still a doubt remained, and in pursuit of other facts, Mr. Trelease, from 

 whom the specimens had been received, was addressed. He replied as 

 follows : 



With regard to these flies, I may state that I have seen them in abundance in all 

 of my jars covered with gauze in which I have reared larvae of either Aletia or 

 Heliothis, being found there while the specimens of Aletia and Heliollris were larvae, 

 and were, as I supposed, attracted by the leaves and bolls put in for the latter to feed 

 upon. I would account for their presence among my pupae [meaning the pupae which 

 he had sent to the department and from which the flies had been bred] by saying that 

 they were there to feed upon the leaves in which the latter were inclosed ; but if they 

 have been bred from the pupae, I have nothing more to say. I find them in the field 

 about the pupae of Aletia, and had supposed that they might sometimes feed upon 

 the little fluid left in the pupa skins after the exclusion of the moth, since they con- 

 gregate in these empty skins. 



Among a lot of cotton-worm chrysalides received August 28 were 

 many which were in all stages of demolition from being devoured by 

 these Phora larvae. Some specimens contained fifty or more. As Mr. 

 Trelease collected only those pupae for transmission which were still 



