THE SAND-WASPS. 261 



operation. Nevertlieless tlie oeconomy of tlie insects 

 of this tribe offers many points of interest^ and their 

 habits are well worthy of observation. Of all the 

 Aculeate Hymenoptera these insects certainly ap- 

 proach most closely to the Entoinophaga, and like 

 these, their office in the oeconomy of nature appears 

 to be the limitation of the multiplication of certain 

 other species of insects. 



In walking over a sandy district in the hot days of 



i summer_, we cannot fail to have our attention drawn 



! to some species of these insects, several of which 



abound in such situations. The common Pompilus 



• fuscus, with its black pubescent body, and the red 



base of its abdomen marked Avith three blackish trans- 



( verse bands, may be seen alighting* on the hot sand, 



I standing still for a moment, or running a little way, 



I vibrating its dark-brown wings, and evidently on the 



; look-out for the unfortunate spiders, which are 



destined to become the food of its progeny. It is 



not always an easy matter to capture this species, as 



its senses appear to be nearly as quick as its motions ; 



and when the entomologist succeeds in his endeavours, 



he vnll do well to be careful in securing his treasure, 



which is gifted with an extraordinary power of stinging. 



Scarcely less abundant than the preceding species, 



but larger and of a more formidable appearance, is the 



I Ammophila sabulosa, an insect which measures nearly 



: an inch in length, and is remarkable for the structure 



of its abdomen. The first two segments of this 



region of the body are considerably narrowed, forming 



a long footstalk, at the end of which the remaining 



i segments constitute an ovate club ; the general colour 



of the body and limbs is black, but the hinder portion 



of the second, the whole of the third, and the base of 



