744 BOSTON JOURNAL 



I have hardly a doubt that the individual here given as a 

 variety is a distinct species; but as my specimens are much 

 mutilated, I am unwilling to venture to separate them. 



POMPILUS Fabr. Latr. 



1. P. CALIPTERUS. — ^W^ings bifasciate; antennae and feet 

 honey -yellow. 



Inhabits Indiana. 



Body black, polished, slightly pruinose : antennae honey-yellow, 

 a little dusky towards the tip : nasus, at tip, mandibles and palpi 

 honey-yellow : wings hyaline, with a blackish band on the mid- 

 dle and a much broader one crossing the second and third cubital 

 cellules ; the latter hardly reaches the anal margin ; basal series 

 of transverse nervures dislocated at the externo-medial nervure : 

 feet honey-yellow; tarsi with the ultimate joint blackish; inter- 

 mediate and posterior pairs of feet more or less varied with 

 blackish. 



Length three-tenths of an inch. 



A very pretty species, of which I have as yet obtained but 

 two specimens. It is probably allied to the hifasciatus Fabr. 



2. P. ARCHITECTUS. — Dark purple ; wings hyaline. [303] 

 Inhabits Ohio. 



9 Body dark bluish-purple, somewhat hairy : head black in 

 front, with short, dense, yellowish-cinereous hair : mandibles at 

 tip piceous : wing-scale dark piceous : wings hyaline, nervures 

 blackish : second and third cubital cellules not unusually con- 

 tracted at the radial cellule, but almost equal in that part, feet 

 black : tergum, anal segment polished. 



Length about three-tenths of an inch. 



This insect forms neat mud nests under prostrate logs and 

 stones. They consist of short cylinders, agglutinated together 

 alternately, and each composed of little pellets of mud, com- 

 pressed, or rather appressed to each other. When these are 

 adjusted to their places on the edge of the cylinder, each has a 

 fusiform shape and the slender end of one laps over that of 

 another, and the convex part of the pellet of the succeeding 

 layer is placed against this duplicature so as to restore the equal- 

 ity of the edge. This arrangement gives the surface an alternate 



appearance. 



[Vol. I. 



