1 904] JOHNSON : — FO UR NE W DIP TERA I 7 



the light for a number of years, the pile is much lighter than on a specimen in my 

 collection from "N. 111.," and the abdomen is reddish brown not blackish brown. 

 The wings of the two specimens show a marked difference in venation, the cross 

 vein dividing the first posterior cell is wanting in the specimen from Illinois. Mr. 

 Melander refers to the position of this vein as inconstant. The Massachusetts 

 specimen has the projection on the costa very pronounced, with the sides nearly 

 parallel, apex truncate, edges narrowly margined, and the center hyaline; in the 

 other specimen the projection is conical and the costa more thickened. 



The distribution of this rare species, based on six specimens, is as follows : 

 Type from Dallas, Tex., Sept. 20; Austin, Tex., and Rochester, Wis. (Melander); 

 N. 111. (Bolter) , Mass. (Packard). The 9 is unknown. One of the Texas speci- 

 mens was found by Mr. Melander entangled in web of Agelcna naevia Bosc, 

 having apparently issued from the shrivelled spider lying close by. The above 

 synonymy was given by Dr. C. F. Adams in the Kansas Univ. Sci. Bull., XII, 32, 

 1903. 



Acrocera fasciata Wiedemann. 



Two specimens which agree in every respect with the brief description given 

 by Wiedemann were bred from Lycosa stonei by Dr. T. H. Montgomery, Jr. (Proc. 

 Acad. Nat. Sci. Phila. 1903, p. 68) who refers to the parasites as follows: — "One 

 male and six females died from the effects of an endoparasitic dipterous larva. 

 One spider contained two of these parasites, the others one each. After the para- 

 site, whose bulk nearly equals that of the body of the spider, has eaten away most 

 of the soft parts of the spider, it emerges through a hole it makes in the wall of 

 the abdomen of the spider, and this emergence kills the host. It is strange that 

 these spiders should live so long with such a huge parasite within them. A short 

 time before the parasite escapes the spider acts in a peculiar manner, walking 

 about spasmodically and often spinning aimlessly." 



The larva is light yellow, 5 mm. in length, and resembles the figure given by 

 Mr. J. H. Emerton (Psyche V, 404, 1890,) except that is more contracted towards 

 the head, probably due to the alcohol in which it is preserved. The posterior half 

 is globular in form, the anterior half showing quite clearly segmentation, and bear 

 seven short, transverse, blackish, bristly roughened, pseudopodal ridges ; on the 

 posterior portion the ridges are usually divided and indicated by two small spots. 

 The mouth parts show a mandibular structure. 



The spiders from which Dr. Montgomery bred this species were collected in 

 or near Philadelphia, Pa., and the two flies obtained, measure respectively 4 and 6 



