262 INDIRECT BENEFITS DERIVED FROM INSECTS. 



Bembex and MeUinus confine themselves to Diptera^ 

 the former preying upon Elophiliis tena,r, Bombi/Ui^ and 

 the like^; the latter amongst others ridding us of the 

 troublesome Stomoxi/s calcitrans. One of these last I 

 have observed stationed on dung watching for flies, 

 which, when seized, she carried to her burrow. 



Vespa spinipes feeds upon certain green apod larvae, 

 of which the female deposits ten or twelve with each 

 egg. Ammophila vulgaris destroys caterpillars of a 

 larger size ; and it is probable that most of the other 

 Vespoid and Sphecoid Hi/menoptera^\'\z. TrypoxyJon^ 

 Philanthus^ Larra, Crabro^ &c. assist in this great work. 



Pompilus^ to which genus probably several species 

 mentioned by Reaumur as preying on these insects 

 should be referred, has it in charge to keep the num- 

 ber of spiders within due bounds : and some Ammo- 

 philcB lend their aid. One of these last, mentioned by 

 Catesby, (Sphex ccerulea, Linn.), has been known to 

 seize a spider eight times its own weight''. Another 

 species of this genus, which is common in the Isle of 

 France, attacks an insect still more difficult, one would 

 think, to turn to its purpose, the all-devouring Blatta, 

 and is therefore one of the great benefactors to man- 

 kind. When this insect perceives a Blatta (called there 

 Kakerlac and Cancrelas) it stops immediately : both 

 animals eye each other ; but in an instant the sand-wasp 

 darts upon its prey, seizes it by the muzzle with its 

 strong jaws, and bending its abdomen underneath it, 

 pierces it with its fatal sting. Sure of its victim, it now 

 walks or flies away, leaving the poison to work its ef- 

 fect; but in a short time returns, and, finding it de- 



** Latreillc, Observations nouvelles sur les Hymenopleres, Annal, de 

 Mas. 11. " Nal. Hist, of Carolina, ii. 105. 



