

xx vi President 1 s Address. [Aug. 28,- 



true the insect might very well have saved herself this trouble. The 

 enemy is everywhere round her. Close by her galleries I see the 

 Chrysidae ; the Anthrax and Bombylius, these elegant and conspicuous 

 flies with their thick coating of high-pile velvet are also numerous, and 

 these small Tachynaria flies are not watching her for nothing. 



Let us sit at leisure before this sand-bank, where I have spent 

 already so many hours. Two species of Bembex are very common 

 here; and it is easy to observe them. 



There comes one ; without any hesitation she alights on a spot 

 where no aperture is visible. She carries a fly, a good-sized one. The 

 fore-legs so well adapted for the removal of sand are at work ; the 

 insect disappears ; the sand behind it falls again. At a short distance 

 from the surface the ground is damper, and therefore firmer ; here is 

 the gallery, and near the bottom a legless grub surrounded by the 

 debris of several varieties of flies. 



The provender is deposited close to the grub, and apparently time 

 is precious, because, as soon as the fly is in its proper place, the 

 mother is of! ; the fore-legs brush away the sand, which, falling again 

 behind her, forms a screen in front of the entrance. 



Unlike the JIyme?ioptera, whose habits I have been explaining to 

 you, the Bembex supplies her larva daily with food. She will come 

 again when she thinks that the larder is empty, bringing with her 

 another fly, and she serves out the ration according to the appetite of 

 her offspring. There is now no necessity for the skilful use of the 

 poisoned stiletto ; paralysis is no longer required. If the food has 

 dried up before the larva has consumed it, there will be another, insect 

 brought to replace it. One can easily conceive the labour involved by 

 this habit so dissimilar to that of other solitary bees and wasps, because 

 the Bembex has more than one burrow to supply. 



A mother watching over her young, regulating the amount of food 

 destined to it ; there is indeed a highly-developed sense of intelligence. . 

 Yes to be sure ; but . . . Here also we must point out deficiencies. . 

 In some galleries the grub is not alone. Here it lies, fat, yellow, 

 gnawing away at its provender. But gnawing at the same morsel 

 there are also several other grubs, smaller, and much more active. 

 Any doubt at their identity is soon set at rest ; they are, doubtless, 

 grubs of a fly, dipterous larvae. But where do these parasites come 

 from ? It is not easy for an insect unprovided with the powerful rakes 

 of a Bembex to penetrate the screen of sand. The mystery is soon 

 explained ; and, like the Odynerus, like the Sphex, the Bembex gives 

 us a proof of the possession of a very limited intelligence after all. 



Dotted on that sand-bank are a good many Tachynaria flies. They 

 are squatting on the ground near the entrance to the galleries. The 

 Bembex arrives carrying her fly. She must first effect an entrance, 



