F08S0R ES SPH ECID^. Ill 



and second submarginal cells combined ; marginal cell obliquely trun- 

 cate at tip Mygnimia Smith. 



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

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



I'opsis Fabr. 



This large and interestintr family has been monographed in a paper 

 entitled " Notes on the Pompilidne 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 sjiecies, e. g. of Agenia, the legs of which are not fitted for 

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

 walls similar to those made by Pelopoeus, a genus of the Sphecidae. 

 The species of Pcjh-d-*, which are among the largest of our hymenop- 

 tera, prey ujwn 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 

 referred to an article published by the late Benj. D. Walsh, in the 

 first volume of the "American Entomologist," pp. 122-148. 



Mr. Westwood (Introd. Mod. Class. Ins. ii, 203) includes the Pom- 

 pilida- as a subfamily of Sphecidae, which 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 Amnw- 

 phila, Sphex, Pelopaeiis or any of the genera of his first subfamily. 



Family SPHECIDiE. 



This family has the prothorax narrowed anteriorly and forming a 

 sort of neck, but the posterior angles are not prolonged to the base 

 of the wings, 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 are usually clothed 

 with long, thin pubescence. 



_ The species mostly burrow into sand-banks, and provision their 

 cells with caterpillars and spiders. 



The following table will assist in separating the genera: . 



