OF WASHINGTON, VOLUME XIX, 1917 95 



4. Palpi apparently not present; mandibles tridentafe, th<> middle tooth 



longest, lateral teeth equal Idiogastra. 



-Palpi papilliform; mandibles various, if dentate llie ventral tooth is 

 longest Clistogastra. 



GENUS ORYSSUS LATREILLE. 



In originally proposing the genus Oryssus Latreillc used the 

 spelling Orussus, but in his later works he corrected this lapsus to 

 Oryssus. This later spelling is the better form and has been the 

 one constantly used and should therefore be retained. 



In Mr. Rohwer's synopsis of the North American species of 

 Oryssus (Proc. U. S. Nat. Mus., vol. 43, 1912, pp. 141-158) the 

 shape of the hypopygidium was used as a specific character and 

 from the material which was examined at that time it held very 

 satisfactorily. Considerable new material coming in from the 

 West and from the East indicates that although these characters 

 hold for a great proportion of the specimens there occasionally 

 arises a case when it is difficult to determine in which group the 

 individual should be placed. It seems therefore that this can- 

 not be used as a" specific character especially as all of the indi- 

 viduals in one of the recent series came from the same locality 

 at the same time and under similar conditions. Sd far in the 

 material now available the emargination of the facial flange 

 (== clypeus, authors) proves reliable but it seems possible that 

 this character too may be found to vary. If this is the case 

 Group B. II will be a species and known as occidental/*. 



Oryssus terminalis Newman. 



Oryssus terminalis Newman, Ent. Mag., vol. V, 1838, p. 486; Rohwer, Proc. 



U. S. Nat. Mus., vol. 43, 1912, p. 150. 

 Oryssus haemorrhoidalis Harris, Rept. Insects of Mass., 1841, p. 394; 



Rohwer, I.e., p. 151. 



A number of specimens of this species have been collected 

 around Harrisburg by W. S. Fisher. We have not yet been able to 

 locate a male to go with this female, and it is possible that the 

 male of this species will have the abdomen entirely black and that 

 it is at present confused under the name, Nayi. 



Oryssus occidentalis Cresson. 



Oryssus occidentalis Cresson, Proe. Ent. Section, Acad. Nat. Sci., Phila., 



1879, p. 9; Rohwer, I.e., p. 153. 

 Oryssus abietis Rohwer, I.e., p. 153. 



In a series of specimens collected recently by Mr. Burke and 

 his associates there are a few individuals which are intermediate 

 in the shape of the hypopygidium between the type of occidentalis 



