FOSSORES — sphecid.t:. Ill 



and second siihmarginal cells combined ; marginal cell ()l)li(|iu'ly trun- 

 cate at tip iflygniiiiia Smith. 



Second submargiual cell much larger than the third, receiving the first re- 

 current nervure near the base; marginal cell obtusely pointed at tip. 



Pepsis Fabr. 



Thi.s large and intere!<tiiig family has been monographed in a paper 

 entitled " Notes on the Pom])ilid:e of North America" published in 

 the first volume of these Transactions, 1867, wherein the genera and 

 species then known are described at length. Since then quite a num- 

 ber of species have been added to our fauna, as will be seen in the 

 list given further on. 



The species of this family generally burrow in sand banks, pro- 

 visioning their cells mostly with spiders, which they first paralyze. 

 Some species, e. g. of Ageiila, the legs of wdiich are not fitted for 

 burrowing, construct mud-cells, placed irregularly side by side upon 

 walls similar to those made by Pelopocus, a genus of the Sphecidse. 

 The species of Pepds, which are among the largest of our hymenop- 

 tera, jirey upon the Tarantula, an interesting account of which has 

 been published by Mr. Buckley in the first volume of the Proceed- 

 ings of the Entomological Society of Philadelphia. For an exceed- 

 ingly interesting account of the habits of these insects, the reader is 

 refen-ed to an article published by the late Benj. I). Walsh, in the 

 first volume of the " American Entomologist," pp. 122-143. 



Mr. Westwood (Introd. Mod. C'lass. Ins. ii, 203) includes the Pom- 

 pilid* as a subfamily of Sphecidse, wdiich he, curiously enough, char- 

 acterizes as " having the collar laterally dilated and extending as far 

 as the base of the wings," which is certainly not the case in AmDio- 

 phila, Sphex, Pelopceus or any of the genera of his first subfansily. 



Family SPHECID^. 



This family has the i)rothorax narrowed anteriorlv and foi'inino; a 

 sort of neck, but the j)osterior angles are not prolonged to the base 

 of the ^^ings, as is the case in the preceding families of the Fossores ; 

 the basal segment of the abdomen is narrowed generally into a long, 

 smooth, round petiole, and the head and thorax arc usually clothed 

 with long, thin pubescence. 



The species mostly burrow into sand-banks, and provisiim their 

 cells with caterpillars and spiders. 



The following table will assist in separating the genera: 



