Packaud] insects as ARCHITECTS. 319 



than the sand wasps. The different species of Crabro, with 

 their hxrge cubical heads, tlie Philanthus (Fig. 248) and 

 Cerceris, refit old nail holes and tunnel rotten wood, filling 

 their holes Avitli aphides, caterpillars, beetles and spiders, etc. 

 The European Philanthus apivorus has the unfortunate habit 

 of provisioning its nest with hone}^ bees ; so ^j^ 243 

 also with a species of Cerceris. The smaller, 

 blackish species have the most interesting 

 habits. In Europe, according to Prof. West- 

 wood, the prey of a species of Oxybelus con- 

 sists of flies, " which it has a peculiar mode Philanthus. 

 of carr3-ing by the hind legs the while it either opens the 

 aperture of its burrow, or else forms a new one with its 

 anterior pair." 



A Tr3-pox3'lon wasp was detected in England frequenting 

 the holes of a post preoccupied by a species of Od3-nerus, 

 a solitary wasp closely allied to the social paper wasps, 

 "into which it conveyed a small round ball, or pellet, con- 

 taining about fifty individuals of a species of Aphis ; this the 

 Odyncrus, upon her return, invariably turned out, flying out 

 with it, held l)y her legs, to the distance of about a foot from 

 the aperture of her cell, where she hovered for a moment, 

 and then let it fall ; and this was constantly the case till the 

 Trypoxylon had sufficient time to mortar up the orifice of 

 the hole, and the Odyncrus was then entirely excluded ; for 

 although she would return to the spot repeatedly', she never 

 endeavored to force the entrance, but flew off to seek another 

 hole elscwiierc." The stems of the syringa, elder, black- 

 berry and other pithy shrubs are also favorite nesting places 

 of these wood wasps. Several species have been found by 

 Mr. Angus nesting in the stems of the syringa; all their 

 nests have a family resemblance, being simple tunnels, with- 

 out any pretensions to architectural skill. 



The stems of the blackberry or syringa arc often tenanted 

 by the little green Ceratina bee. Figure 249 represents a 



31 



