THE DIPLOPTERA. 265 



Although the insects of the preceding tribe are 

 denominated Fossoria, or as it were diggers, par ex- 

 cellence, it must not be supposed that they are the 

 only Hymenoptera which burrow in the ground, for 

 they possess this habit in common with a considerable 

 majority of the other Aculeata, whilst some members 

 of the tribe to which we now come, agree with them 

 so closely in most particulars of their oeconomy, that 

 if we looked to habit alone, we might consider them 

 as forming part of the same group. This is the tribe 

 of Wasps, to which the name of DIPLOPTERA* is given, 

 in allusion to the singular arrangement of the wings, 

 which fold up longitudinally in repose, so as to form 

 a pair of long narrow strips, lying parallel to each 

 other on each side of the back of the insect. In other 

 respects they agree pretty closely with the Fossorial 

 .Hymenoptera in most of their characters, and this is 

 the case especially with the solitary species, the habits 

 of which are also nearly identical with those of the 

 insects last referred to. 



For an example of these Solitary Wasps we need 

 not go very far. Hovering over the shrubs, and 

 especially rose-trees in our gardens in the summer 

 months, we may almost constantly see a small Wasp, 

 measuring nearly half-an-inch in length, of a black 

 colour, with some yellow spots on the face and thorax, 

 and with five of the segments of the abdomen nar- 

 rowly edged with yellow. The second abdominal 

 segment is of very large size, occupying nearly the 

 half of this region of the body, and as this is the first 

 which exhibits the yellow margin, the latter is of 

 course removed to a considerable distance from the 

 base of the abdomen, whilst the small and gradually 

 * Gr. diplos, double, pteron, & wing. 



N 



