Il8 ENTOMOLOGICAL NEWS. [May^ 



thus ><: at the outer end of the discal cell. The venation of 

 D. rufithorax is perhaps the most variable of any known species. 

 The vein that separates the fourth and fifth posterior cell is as 

 often incomplete (fig. 2) as it is complete (fig. 3). While in three 

 specimens one wing has the former and the other the latter char- 

 acter. Two or three specimens show another peculiar variation 



Fig. 2. Fig. 3. 



(also shown in fig. 2) in having stumps of veins projecting from 



the third longitudinal vein, one near the anterior branch, and two 



from the branch, one near the junction the other near the tip; 



there is also one on the first branch of the longitudinal vein about 



half way between the discal cell and the posterior margin. The 



above facts will, as has already been shown by Dr. Williston, 



cause the abandonment in this case of ' ' four posterior cells' ' as 



a generic character. 



Dialysis elongata Say. 



Stygia elongata Say, Jour. Acad. Nat. Sci. iii, 41, 1823 ; Compl. Wr. 



II, f. 5- 

 Anthrax elongata Wiedemann, Auss. Zw. i, 315, 1828. 

 Lomatia elongata Wied., Auss. Zw. i, 561 ; tab. ii, f. 6. 

 Xylophagus americanusWied.} Walker, List, etc., i, 128, 1848. 

 Dialysis dissitnilis Walker, Dipt. Saund. iv, 1856. 

 Triptotricha dissimilis (Walk.) Osten Sacken, Berl. Ent. Zeit. 1883, 



295- 

 Agnotomyia elongata (Say), Williston. Entom. Amer. u, 106, 1886. 

 Dialysis dissimilis (Wa^k.) Williston, Kans. Univ. Quart, iii, 265, 1895. 

 Dialysis elongata (Say) Williston, Kan. Univ. Quart, iii, 265, 1895. 



From descriptions, a study of Walker's type (through the 



kindness of Mr. E. E. Austen), and an examination of a large 



amount of material, as the species is quite common in the vicinity 



of Philadelphia, I can only arrive at the above conclusion as to 



synonymy. Say described a male, while Walker's specimen, 



the type of the genus, is a female. 



Dialysis fasciventris Loew. 



Triptotricha fasciventris Loew, Berl. Ent. Zeit. 1874, 380. 

 (^. — Length 8 mm. Head black ; face, frontal triangle and occiput 

 covered with a silvery white pubescence, mouth parts and the first and 

 second joints of the antennae yellowish, third joint and style brown, ocelli 

 reddish. Thorax black, shining, with minute yellow hair, sternum with 

 silvery pubescence, humeri and the outer half of the scutellum brownish. 



