1890.] President' *s Address, xxv 



and the abdomen carving under the victim punctures the ganglionic 

 mass. The deed is done. 



It is no longer an unarmed prey that the Pompilus has paralysed at 

 leisure ; it is during a sharp struggle where the assailant has not 

 always the best of it that the fatal thrust must be given, and it is a 

 very common occurrence to see the Pompilus carrying a spider often 

 considerably more bulky than herself, stop and insert her sting again 

 in the ganglionic region. Has she felt a renewal of activity in the 

 paralysed mass she is now dragging, which makes her fear for her 

 own safety ? I should say it is so, because on four different occasions 

 small Pompilid, caught immediately after the end of the fight and 

 placed together with their victims in a glass tube, were found dead the 

 following morning ; the spiders had recoyered from their lethargy, and 

 being nocturnal had had their revenge ; never, however, were the 

 Hymenoptera, eaten. Pelopoeus spirifex is sometimes seen attacking 

 spiders on their web. Doubtless she is well armed, and if she only 

 succeeds in inserting her sting the spider lies at her mercy. But the 

 Arachnid, beside her own weapons, is an expert at throwing her 

 threads, and great has been the number of Pelopoeus I have seen, the 

 corpses of which, sucked dry and lying entangled in a web, testify to 

 the heroism of the maternal instinct. 



I think I have now substantiated what I told you a little while ago 

 about the degree of adaptation to a purpose displayed by these solitary 

 wasps, and yet they cannot be credited ■ w T ith the same amount of 

 intelligence in all their actions. If you meet a Pompilus, Sphex, or an 

 Ammophila carrying her prey to the hole, you will generally see that 

 she leaves it on the threshold, and enters her gallery. Remove the 

 caterpillar or spider a few inches from the entrance, she will drag it 

 back to the opening, and will abandon it on the same place and go in 

 again for her subterranean inspection ; remove the spoils altogether, 

 and you will often see the wasp, instead of flying away, setting to 

 close and cement the aperture. I have often succeeded in repeating 

 here that experiment of Fabre with Pelopceus spirifex, and Ammophila 

 capensis, as well as with several species of Pompilus. The closing 

 and cementing of the hole is done with too much care not to lead us to 

 believe that the insect has come to the conclusion that its task is 

 finished. I have found by reopening the cells, either an insufficient 

 quantity of caterpillars or spiders, or, oftener, no provender at all. 



As for the repeated entrance to the hole, after leaving the provender 

 on the threshold, I thought at first that it was to enlarge the cell 

 according to the size of jbhe victim which was going to be stored in it ; 

 but, as 1 never saw the Sphex carrying out the excavated material, I 

 am induced to suppose that it is in order to see if no intruder in the 

 shape of a parasite has already taken possession. If my surmise is 



