94 AMERICAN HYMENOPTERA. 



of the same general aspect. It differs from lepida by the much 

 broader face and smaller and less prominent eyes, and in the broader, 

 truncate apical plate of the abdomen, which is conspicuously notched 

 on each side subapically. In lepida the apical part (nearly half) of 

 the basal joint of middle tarsus is ferruginous and somewhat con- 

 stricted, but in hirkmanniella the whole joint is black and normal 

 though slender. 



The following table will facilitate the separation of the above two 

 species from their allies: 



Third autennal joint very short, broader than long seen from in front; clypeus 

 entirely yellow ; mandibles with a small yellow spot; abdomen very 

 shiny fedoris Ckll, 



Third antennal joint longer than broad, seen from in front; abdomen less 

 shiny 1. 



1. Abdomen very distinctly banded 2. 



Abdomen not very distinctly banded, or not banded 3. 



2. Face very narrow, conspicuously narrower than the combined width of the 



eyes, as seen from in front lepida (('ress. ). 



Face broader than combined width of eyes birkinauiiiella Ckll. 



3. Mesothorax shiny and conspicuously punctured; mandibles with a minute 



yellow spot gillettei snoviana Ckll- 



Mesothorax dull ; mandibles with no yellow spot 4. 



4. Last ventral segment with two conspicuous longitudinal keels; size smaller. 



lerritella Ckll. 



Last ventral segment without such keels; size larger; narrow upper edge of 



clypeus black 5. 



5. Abdominal segments 4-6 with much light hair; third antennal joint short. 



tVater (Cress.). 

 Abdominal segments 4-6 with black hair; third antennal joint longer. 



triittte Ckll. 



Tetralonia dilecta (Cresson). 



Barela Mesa, New Mexico [Anna Gohrmann) ; Baldwin, Kansas 

 i^Bridwell) ; Illinois {Robertson); Fort Collins, Colorado (^Colorado 

 Agr. College) ; Boulder, Colorado, at flowers of Aragallus, June 10, 

 1905, 9 {W. P. Cockerell). This unfortunate species has been 

 repeatedly confused with T. frater and T. speciosa, but it is easily 

 known by the hooked spurs. It is the T. speciosa of Robertson's 

 table in Trans. Am. Ent. Soc, xxxi, 366-367, and of my descrip- 

 tion in Entomologist, June, 1905, p. 148. T. frater aragalli Ckll., 

 which is very similar in appearance, has the spurs of hind leg quite 

 simple. The following table will be useful for the .separation of 

 several females having tlie general appearance of dilecta: 



