206 HTMENOPTERA. 



tenuas is miuiite, and the hind femora are thick, Ijut not ser- 

 rated, and beneath armed with a tooth near the tip. 



The wings are rudimentary so tliat it does not quit the cell. 

 Newport states that the larva is flat, ver}^ hair}", and spins a 

 silken cocoon when about to pupate. It is an "external feed- 

 ing parasite" consuming the pupa as well as the lai'va of An- 

 thophorabia. The imago appears about the last of June, 

 perforating the cell of the bee. It also lives in the nests of 

 Osmia, Anthophora, and Odynerus. 



The genus Antliojpliorabia is so-called from being a parasite on 

 Anthophora. The males differ remarkably from the females, 

 especially in having simple instead of compound ej-es, besides 

 the usual three ocelli. A. megachiUs Pack. (Plate 4 ; fig. 7, 

 larva ; 7 a, pupa) is a parasite on a species of Megachile. 

 The larva is white, short and thick, cjdindrical, wit-h both 

 extremities much alike ; the segments are slightly convex, and 

 the terminal ring is orbicular and rather large. Length, .04 

 inch, being one- third as broad as long. On opening the cells 

 of Megachile, we found nearlj'' a dozen containing these para- 

 sites, of which 150 larvce were counted clustering on the out- 

 side of a dead and dry Megachile larva. In England they 

 occur, according to Newport's observations, in much less num- 

 bers, as he found from thirty to fifty in a cell of Anthophora. 

 A few females hatched out in the middle of October, and there 

 were a few pupas left, but the majority wintered over in the' 

 larva state, and a new and larger brood appeared in the spring. 



Perilamjnts is a beautiful genus, with its shining, metallic 

 tints. The eleven-jointed antennte ai-e short, lying when at 

 rest in a deep frontal furrow. The head is large, while the 

 abdomen is slightly pedicclled, being short, contracted, with 

 the ovipositor concealed. P. jplatygaster Say and P. triangu- 

 laris Say were described from Indiana. 



The numerous species of Pteromalus often oviposit in the 

 larvse of butterflies. In this genus the antennse are inserted 

 in the middle of the front. The abdomen is nearly sessile, ob- 

 tusely triangular, or acutely ovate in form, with the ovipositor 

 concealed. The femora are slender. There are about thi-ee 

 hundred species known to inhabit Europe. Pteromalus va- 

 nesscB Harris is a parasite on Vanessa Antiopa. P. clisio- 



