HYMENOPTERA. ACULEATA. 209 



is made a sudden attempt would not succeed : the fly 

 is the insect of quickest flight, therefore a degree of 

 artifice is necessary. This is managed by running past 

 the victim slowly, and apparently in an unconscious 

 manner, until the poor fly is caught unawares and carried 

 off by the MeUinus to her burrow. The first fly being" 

 deposited, an egg is laid. The necessary number of flies 

 are soon secured, and her task is completed ; but some- 

 times she is interrupted by rainy weather, and it is some 

 days before she can store up the quantity required. A 

 larva found feeding became full fed in ten days; six flies 

 were devoured, the heads, harder parts of the thorax, por- 

 tions of the abdomen, and the legs being left untouched. 

 The larva spins a tough, thin, brown silk cocoon, passes 

 the winter and spring in the larva state, changes to the 

 nymph on the approach of summer, and appears about 

 the beginning of autumn in the perfect state." 



The seventh family, Crabronid, much resembles the 

 preceding in general character, but from it the three 

 principal genera, Trypoxylon, Crabro, Oxybelus, are 

 easily known from all other of the Fossores, by the 

 presence of only one submarginal cell. The first genus, 

 Trypoxylon, is distinguished by the eyes, which are deeply 

 cut, or kidney-shaped, and the wings with one tapering 

 marginal, and one submarginal cell. It contains three 

 species, all common. T. figulus is to be found every- 

 where. It burrows in sandy banks, sometimes forming 

 colonies, and provides its Iarva3 with spiders. It is a dusky 

 black insect, long, with a long somewhat slender club- 

 shaped abdomen, thickest at the end, contracted at the 

 close of each segment, and with a slight hump near the 

 base. The other two species are also black and similar 

 in form. T. claviceruyn and T. attenuatum, burrow in 





