SPHEGIDAE PHILANTHIDES 



125 



intermediate between the two great divisions of the Fossores, for 

 the pronotal lobe extends nearly or quite as far back as the 

 tegulae, and in Philanthus the two come into almost actual 

 contiguity. 



The species of the genus Cerceris are numerous in Europe, 

 and several of them are known to make luirrows in the ground,/ 

 and store them w4th beetles for the benefit of the future larvae./ 

 The beetles chosen differ in family according to the species or 

 Cerceris ; Ijut it appears from the observations of Fabre and Dnfour 

 that one kind of Cerceris 

 never in its selection goes 

 out of the limits of a 

 particular family of 

 beetles, but, curiously 

 enough, will take Insects 

 most dissimilar in form 

 and colour provided they 

 belong to the proper 

 family. This choice, so 

 wide in one direction and 

 so limited in another, 

 seems to point to the 

 existence of some sense, 

 of the nature of which we are unaware, that determines the 

 selection made by the Insect. In the case of our British species 

 of Cerceris, Smith observed C. are/iaria carrying to its nest Cur- 

 culionidae of very diverse forms ; while C. lahiata used a beetle 

 ■ — Haltica iabida — of the family Chrysomelidae. 



The beetles, after being caught, are stung in the chief 

 articulation of the body, that, namely, between the pro- and 

 mesothorax. Cerceris hiqyresticidct confines itself exclusively to 

 beetles of the family Buprestidae. It was by observations on 

 this Insect that Dufour first discovered the fact that the Insects ; 

 stored up do not decay : he thought, however, that this w^as due 

 to the liquid injected by the wasp exercising some antiseptic 

 power ; but the observations of Fabre have shown that the pre-f 

 servation in a fresh state is due to life not being extinguished ; 

 the stillness, almost as if of death, being due to the destruction 

 of the functional activity of the nerve centres that govern the 

 movements of the limbs. 



Fig. 49. — Philanthus triangidum $. Britain. 



