424 



Marvels of Insect Life, 



at once bit the beetle-grub between the sixth and seventh segments of its 

 body, and buried the first three segments of its own body in tliat of its victim. In 

 this position the wasp-grub sucks and sucks until nothing but the skin of the beetle- 

 grub is left ; but by that time the wasp-grub is full fed and able to transform itself 

 into a chrysalis, from which in due time the wasp emerges. Now, in this case 

 the task of the himting mother-wasp may be comparatively easy, for the spent-tan 

 in which its victim is found may lie in a heap on the ground where the tanners have 

 thrown it out of the tannery pits ; but in other cases it does not appear so easy. 



In more recent years, Fabre has investigated the operations of the two-banded 

 beetle-eating wasp,^ who selects the grub of the rose-chafei beetle ^ for the food of 

 her young. These grubs are mostly found deep in the nests of the wood-ant, where 

 they feed upon the decaying vegetable matter of which these structures are composed. 

 However, the wasp finds it, and as the chafer-grub is a large one, and b\^ its move- 

 ments might easih^ destroy the egg of the wasp, it is necessary to kill or render it 



insensible. Fabre lays great stress 

 upon the necessity of rendering it 

 helpless without destro3ang life, in 

 order that its body may not 

 putrefy ; but the Peckhams, who 

 have paid special attention to all 

 matters relating to wasps, differ 

 from Fabre in this matter, and 

 say it does not matter if wasp- 

 victims are killed outright, they 

 serve the intended purpose all the 

 same. Fabre says that a struggle 

 ensues, the chafer-grub wriggling 

 to prevent the wasp getting its 

 weapon into the desired spot — 

 the centre of the nerve-ganglia 

 that control the movements of 

 1he chafer-grub ; but ultimately the wasp is successful, the nerve mass is stung, and 

 henceforth the grub is as one paralyzed, alive but incapable of movement or feeling. 

 The cavity that the chafer-grub had made for itself to lie in serves for the cell of 

 the wasp-grub, and the single egg is laid on the under surface well behind the legs. 

 It hatches, and the young wasp-grub pushes its head through the skin of its victim 

 and gradually clears out the rich contents of the hind-body, and when this part is 

 gone it pushes its head further inside and attacks the more forward parts, until 

 the empty skin is left. 



Another species ^ of these beetle-eating wasps chooses the grubs of two 

 related species of chafers* more akin to our cockchafer. The eggs are 

 laid in August or September and hatch about two days later. When 

 full fed the wasp-grub spins a cocoon inside the empty skin of its victim. 

 In this stage it passes through the winter, and in spring becomes a perfect wasp ; 

 but it does not emerge from the earth unlil early in June. 



^ Scnlia bifasciata. * Cctonia aurata. ^ Scolia intcrnnila. * Anoxia. 



The Heath Potter 



Oiieof the smaller of our native waspswho makes, her cells — shown on page 423 

 — in the form of a broad-based vase with a short neck and turned-out lip. 

 Each ceU, made of clay, is furnished with a stock of small caterpillars and a 

 single wasp's egg. 



