Feb., 1909.] Definition of Nysson and of N. aurinotus. 
445 
but the form of the seventh dorsal segment is sufficient to sepa¬ 
rate it, armatus having only two distinct teeth on this segment 
and texanus having four. 
Say’s description of Nysson aurinotus applies equally well to 
armatus and to texanus, with the exception of size (“three-tenth 
of an inch”) in which it agrees precisely with armatus, and not a 
word of his description is at variance with either. But as Say 
did not mention the armature of the abdomen and probably 
knew only the female it is hardly safe to adopt his name for one 
of them to the exclusion of the other. As it is possible that speci¬ 
mens may be found showing connection between the two forms 
of the seventh segment, it is not impossible that Say’s name 
may yet find recognition, but no such connection is now known. 
The name given by Say, meaning “gold-known,” indicates a 
very essential and “prominent” character of texanus, and the 
absence of yellow marks on prothorax and scutellum is charac¬ 
teristic of American Paranyssons and shows clearly that Say’s 
species has no relationship with aequalis. The female specimens 
from Illinois described by Mr. Cresson under aurinotus belong to 
N. aequalis Patton. The males of aequalis and N. plagiatus do 
not differ from one another in form of eighth ventral segment and 
claspers. 
Agenioxenus. To Mr. W. J. Fox is due the credit of referring 
rufiventris to synonomy Avith robinsoni Cress, (cf. Tr. A. E. S., 
1892, p. 57.) The species is easily distinguished from all others 
by the male antennae being longer than both head and thorax. 
Cresson’s figure shows hind cubitus interstitial. 
The specimen in the Riley collection should be re-examined, 
and Walsh’s figure compared. The form of prothorax and of 
metathorax may have been modified in mounting. In Taschen- 
berg’s C. abnormis, <3> from Rio, the venation is as described for 
Agenioxenus. 
