266 bulletin: museum of comparative zoology. 



Leugth. — Female, 19 min.; males, 14-15 mm. 



Described from oue female and two males captured at Cordova, Argentine. 



Tlie female comes very close to neoxenum Kohl, differing from it, according to 

 the description, in that the abdomen is not red but black with a reddish tinge, the 

 face is not pubescent, the mesonotum is not glistening but striate, the reflection 

 of the wings is not violet or steel blue but greenish, and the length is three milli- 

 meters greater than in Kohl's specimen. Remembering, however, what great color 

 variations are present in this group, the difference in the mesonotum seems to be 

 the only one of importance. 



The sole specimen of neoxenum bore the locality record Vancouver Island, but 

 Kohl is of the opinion that this is an error and that it came from Chili. I have 

 seen large collections of Sphecidae from the northwestern Pacific Coast, but have 

 met with nothing like neoxenum ; and as the specimen before me from Argentine 

 so closely resembles Kohl's species, I am also of the opinion that neoxenum is a 

 South American insect, and that with a longer series for study simillimum may 

 prove to be only a color subspecies. 



The males agree quite closely with o>nmissum Kohl, except in the color of the 

 abdomen and in the presence of an excised margin on the sixth ventral abdominal 

 plate. I feel confident that they are the same species as the female here described, 

 and that they are likely to prove to be ommissum. 



If all these assumptions should prove correct, the species will be known as 

 Chlorion {Vriononyx) neoxenum (Kohl). 



Chlorion (Pseudosphex) pumilo (Tasch.). 



S]>h.ex [Pseudosphex) dolichoderus Kohl, Ann. natur. Hofmus. Wien, 1890, 5, 

 p. 870. 



One female specimen. Length, 12 mm. 



Kohl states that dolichoderus is very similar to pumilo, but separates them on 

 the ground that the latter has three cubital cells, the first receiving the first re- 

 current, and the second the second recurrent, while in dolichoderus the first trans- 

 verse cubital vein has disappeared so that both recurrent veins join the elongated 

 first cubital cell. In pumilo the petiole is nearly as long as the hind metatarsus, 

 while in dolichoderus it is only two-thirds the length of this segment. In the 

 former it is as long as the first, second, and half of the third segments of the an- 

 tennal filament taken together, while in the latter it is scarcely equal to that of 

 the first and second. 



In the specimen before me the venation of the right fore wing is that of pumilo, 

 -while that of the left is that of dolichoderus, except that there is a partial first 

 transverse cubital vein extending backward a short distance from the radial cell 

 before it disappears. The length of the petiole is four-fifths ■ that of the hind 

 metatarsus, thus placing this specimen as an intermediate between the two species 

 under consideration, in that regard ; and as only the first segment of the filament 

 is present in each antenna, the third distinction cannot be tested. 



