EXPERIMENTS WITH DINETUS. 39 



Perris, on the contrary, found that even when the 

 whole of the mouth parts were enclosed in gum, insects 

 still retained the power of smell. These observations 

 have been entirely confirmed by Forel and other 

 observers. The explanation, I believe, is that Com- 

 paretti was right, and that the sense of scent is not 

 confined to one part of the body ; that, while it is pos- 

 sessed by the palpi, it is not confined to them. 



It has loDg been observed that insects use their 

 antennse to examine and test their food. This is clearly 

 not an act of hearing ; nor has any one suggested that 

 the antennae are organs of sight or taste. It is obviously 

 more than mere touch — indeed, they do not need to 

 come into actual contact — and is, therefore, probably 

 that of smell. 



This conclusion has been confirmed by many experi- 

 ments. Among those of the older observers some of the 

 most important were made by Perris.* In Dinetus, a 

 genus of the solitary wasps, the female, when absent in 

 search of prey, covers over the orifice to her nest with a 

 little sand. Perris selected two nests, and while the 

 wasps were absent he disturbed the surface round one 

 nest with a piece of stick, and laid his hand (which was 

 rather warm) over the other. The first Dinetus was a 

 little disturbed. She ran about, rapidly vibrating her 

 antennae, and was, perhaps, rather longer than usual in 

 finding the entrance, but lost very little time. The 

 other, he says, " Se trouva de prime abord, beaucoup 

 plus embarrasse ; ma main, dont I'etat de moiteur avait 

 rendu les emanations beaucoup plus actives, avait 

 laisse sur le sable une odeur qui semblait I'etonner, et 



* "Sur le siege de I'odorat dans les articules," Ann. Sci. Nat, 

 1850. 



