IlS ENTOMOLOGICAL NEWS. [May, 



thus x 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. 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. 



n, f. 5. 



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

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

 Xylophagus americanus Wied. ? Walker, List, etc., i, 128, 1848. 

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

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



295- 



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

 Dialysis dissimitis (Walk.) VVilliston, 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 fasciyentris Lpew. 



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



(5\ 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 antenna? yellowish, third joint and style brown, ocelli 

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

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



