1907.] White-geubs and May-beetles. 



471 



The larva, at first almost completely paralyzed by the puncture 

 of the sting and the venom doubtless injected at the same time, 

 slowly revives, recovering presently its full powers of locomotion, 

 so that it is indistinguishable by its behavior from its fellows which 

 have not been stung. The stinging, in this case, is thus a means of 

 quieting the struggles of the grub in a way to permit th^ Tiphia to 

 attach her egg to its back. Commonly, of course, these operations 

 go on under ground. A Tiphia introduced into a breeding-cage con- 

 taining grubs in the earth disappears under ground herself, and does 

 not come out until she has found and infested a grub. 



Repeatedly, where grubs were exposed to attack on the surface 

 of the dirt in breeding-cages, the Tiphia merely stung them at first, 

 and then proceeded to bury them before depositing her egg. For 

 this purpose, she undermined the grub by digging the earth from 

 beneath it,-pulling its body .about by means of her jaws Until it was 

 in proper position to enter the hole, gradually digging deeper, and 

 finally burying it completely. In one case in which the operation 

 was timed, the grub was buried in ten minutes after it was stung. 

 Sometimes the Tiphia abandoned an attempt at burial, and left the 

 grub without placing an egg on it after it was stung. 



Apart from that general exhibition of a wonderful adaptation 

 of its actions to the needs of its prospective progeny which this Ti- 

 phia shares with many other wasps, and especially with those of its 

 own family, there are two points of peculiar interest in this account 

 It is an unmistakable fact that the effect of the poisoning of the 

 grubs by the Tiphia is merely to paralyze the victim temporarily ; to 

 overcome its resistance and reduce it to helplessness while the Tiphia 

 egg is being placed in position. The sting is used as a mere aid in 

 the struggle of the Tiphia with a stronger insect. This fact may 

 point to the explanation of the origin of the remarkable instinct of 

 the solitary wasps to sting and paralyze their prey. 



More remarkable still, however, in the light of our present 

 knowledge of the habits of Tiphia, is its frequent burial of white- 

 grubs exposed to it on the surface of the ground. Since digger- 

 wasps in general are parasites of underground larvae only, since the 

 Tiphia is not known to infest any insects except white-grubs of the 

 genus Lachnosterna, and since in nature it can never find these 

 grubs above ground, its deliberate burial of exposed grubs has all 

 the appearance of a line of action extemporized to meet a previously 

 unknown condition. Either the Tiphia, disturbed at finding its prey 

 e3q)osed, buries this as a result of impulse aided by intelligent con- 

 trivance, or we shall find, when its habits are known in full, that it 



