164 HYMENOPTERA. 



The species of Larra are smaller, and differ from those of 

 Stizus in the long, narrow, very prominent labrum, the shorter 

 clypeus, broader front and longer abdomen, the tip of which is 

 without the broad subtriangular area which is present in Stizus 

 and the other genera of this family. Larra unicincta Say is black- 

 ish, with a single reddish band on the second abdominal ring. 



BEMBECID^E Latreille. We have but two genera, Bembex 

 and Monedula, which have large heads and flattened bodies, 

 bearing a strong resemblance to Syrphus flies from their similar 

 coloration. The labrum is very large and long, triangular, like 

 a beak. The species are very active, flying rapidly about 

 flowers with a loud hum. "The female Bembex burrows in 

 sand to a considerable depth, burying various species of Dip- 

 tera (Syrphidae, Muscidae, etc.), and de'positing her eggs at the 

 same time in company with them, upon which the larvae, when 

 hatched, subsist. When a sufficient store has been collected, 

 the parent closes the mouth of the cell with earth." " An 

 anonymous correspondent in the Entomological Magazine, states 

 that B. rostrata constructs its nests in the soft light sea-sands 

 in the Ionian Islands, and appears to catch its prey (consisting 

 of such flies as frequent the sand ; amongst others, a bottle- 

 green fly) whilst on the wing. He describes the mode in 

 which the female, with astonishing swiftness, scratches its hole 

 with its forelegs like a dog. Bembex tarsata, according to 

 Latreille, provisions its nests with Bombylii" (Westwood.) 

 Dufour states that two Diptera, Panopea carnea and Toxophora 

 fasciata, the latter allied to Systrophus, are parasites on Bem- 

 bex. Mr. F. G. Sanborn has noticed the exceedingly swift 

 flight of our common Bembex fasciata Fabr. on sandy beaches 

 where it is found most abundantly. 



Monedula differs from Bembex in its slenderer body, more 

 clavate antennae, and its shorter, very obtuse labrum. The 

 body is smoother, and most generally more highly colored and 

 more gaily spotted than in Bembex. 



Monedula Carolina Fabr. and M. ^-fasciata Say are common 

 southwards of New England. 



LARRID^E Leach. Mr. F. Smith defines this family as having 

 "mandibles notched exteriorly near the base ; the labrum con- 



