NATHAN BANKS. 233 



deniis it is variable. B. capensis. B. australis and B. sinen- 

 sis have an outer cross-vein between cubitus and anal ; but 

 in B. pilicor7iis and B. strigosus some have it, at least in one 

 wing. The number of cross-veins between the first and 

 second anal is also variable in at least one species, B. occi- 

 dentis ; in B. stigmaterus there is apparently always one such 

 cross-vein. The number of cross-veins under the stigma is 

 fairly constant for many species, but in B. strigosus it varies 

 in one specimen. B. apicalis has but one cross-vein behind 

 the stigma. 



From the variation in venation as shown above I prefer to 

 keep Bittacus in its broad sense, and Harpobiitaciis McLach., 

 Dipiostigma Navas, Thyridates Navas and Haplodictyus 

 Navas as synonyms. I have seen the types of all. Thyri- 

 dates has a rather different appearance, and may prove to 

 have some structural character by which it may be retained 

 as a separate genus. 



The species of Bittanis in the Berlin Museum from Brazil 

 may be separated as follows : 



1. The first (inner) series of gradate veins makes a nearly direct obli- 



que line across the wing 2. 



The upper cross-vein and lower one are farther out than the ends 

 of the middle ones ; the stigma is short, with two cross- 

 veins behind it brasilieiisis. 



2. Stigma with one cross-vein behind ; hind femora and tibia not dark 



at tip flavescens. 



Stigma six or seven times as long as broad, with one cross-vein 



behind ; tips of hind femora and tibia dark...g-eiiiciilatus. 

 Stigma with two cross-veins behind ; tips of hind femora and tibia 



black fenioralis. 



Bittacus alfinis Westw. (in British Museum) has the stigma 

 long and evenly curved behind, and one cross-vein behind it 

 to the radius. 



The three species of Bittacus from South Africa in the 

 Berlin Museum can be separated as follows : 



1. Faint clouds on the origin of the radial sector, its branches and else- 

 where ; tips of all femora and tibife dark ; stigma four times 

 as long as broad, with two cross-veins behind. ..uelmlosiis. 

 No such clouds ; stigma rather shorter ; front femora and tibia not 

 dark at tip 2. 



TRANS. AM. ENT. SOC. , XXXIX. (30) 



