156 Annals Entomological Society of America [Vol. IV, 



Promachus fuscipennis, according to Osten Sacken, is not a 

 North American species and Promachus trapezoidalis Bellardi 

 is rightly included in the genus Mallophora as Williston has 

 stated for it has the claws distinctly blunt at the tips. It may 

 be of interest to state that this latter species has been taken at 

 Brownsville, Texas. Heretofore it was known only from Mexico. 



THE GENUS PROCTACANTHUS. 



Proctacanthus was described by Macquart in 1838. The 

 species falling here are all rather large and robust, the marginal 

 cell is closed, palpi one segmented, antennal bristle bare, veins 

 closing the discal and fourth posterior cells not parallel, the 

 posterior branch of the third vein curves forward to meet the 

 costa before the tip of the wing, anterior branch of the third 

 vein not angulated at base nor does it bear a stump, ovipositor 

 cylindrical and with a terminal circlet of spines which may be 

 very small in some species, abdomen longer than the wings. 

 These characters are all well marked and there is no difficulty 

 in placing the various species in the genus. The venation is 

 much like Erax but the circlet of spines at the tip of the ovi- 

 positor and the lack of silver white segments at the posterior 

 part of the male abdomen are distinctive. 



KEY TO THE SPECIES OF PROCTACANTHUS. 



1. Segments of the abdomen thickly pilose on the sides, very large red species. 



heros 

 Abdomen pollinose or sparsely hairy, smaller species 2 



2. Femora black, tibiae red, the colors strongly contrasting 3 



Femora and tibia of nearly the same color, so there is no strong contrast in 



colors 4 



3. From above the hypopygium is wide, and longer than segments seven and 



eight combined. Male abdomen largely red, female abdomen not red. 



caudatus 

 Hypopygium small, distinctly shorter than segments seven and eight com- 

 bined. Abdomen of both sexes largely red above fulviventris 



4. Abdomen red, except the first segment and anterior border of the second. . . .5 

 Abdomen in large part gray pollinose - 6 



5. Dorsum of the thorax uniformly brown, hypopygium from above wide, appen- 



dages longer than segments seven and eight combined ruf us 



Dorsum of the thorax usually striped with black, hypopygium small, the 

 appendages from above shorter than segments seven and eight com- 

 bined rufiventris 



■6. End lamella of the ovipositor densely pilose, spines at the tip small 7 



End lamella of the ovipositor sparsely hairy and with a circlet of enlarged 



spines at the tip 8 



7. Wings nearly hyaline, many of the veins faintly margined with brownish. . . . 



occidentalis 

 Rather small species, middle of the wing with a large dark colored patch 



coquillettil 



S. Wings hyaline or with only the veins margined with brown 9 



Wings of a uniform brown all over 12 



