( clxxx ) 



that a (^ Aculeate seizes and secures his mate. Now, if we 

 examine the various forms of ^ mandibles in Aculeates, we 

 find that they are sometimes more or less paradoxical ; but it 

 is generally difficult to recognise in them any clear special 

 adaptation to the function of seizing a ^. It is true that in 

 some cases, e. g. Ammophila, the great length and sharpness 

 of the ^ mandibles might suggest such an adaptation ; and I 

 have in my collection a ^ Ammophila actually holding a ? in 

 this manner. But the Ant Formicoxentis (^ grasps his mate 

 exactly in the same way ; and his mandibles are, on the 

 contrary, quite absurdly short and truncate. (When they 

 are closed, their tips scarcely meet across the mouth !) So 

 that the suitability of these organs to act as a forceps cannot 

 apparently be measured by their length or sharpness. Again, 

 a " tooth " or spinose process on the lower side of the mandibles 

 is sometimes a,^ chai'acter {Andrena apicata, fncata, lapponica, 

 etc.), and this might conceivably improve their grip in certain 

 cases. But the phenomenon is not a very common one, and, 

 as well as the cases of unusually long and sharp $ mandibles, 

 may possibly be connected (as Darwin explains the latter in 

 Ammophila) with the pugnacity of rival $ ^ (cf . stags' horns, 

 boars' tusks, etc.). I do not, however, remember to have 

 myself ever seen them so used, but only for holding the ?. 



Charming, taken in a very wide sense, as including all ways 

 in which a ,$ naay dazzle, or fascinate, or attract, or establish 

 an understanding with a ?, by appealing to some sense or 

 susceptibility peculiar to that sex in a particular species, 

 might account (as it seems to me) for almost any one of the 

 ^ characters hereafter to be described. Some of them, however, 

 consisting in exceptional size or complexity of structures which 

 are known to be sense-organs, might come more naturally 

 under the category of Discovering. 



For instance (1) the eyes of $ Aculeates are generally larger 

 than those of their ^ $, e. g. in most Ants, in several Bomhus 

 spp. as confusihs and m^endax (Bees), in Tachytes and Tachysphex 

 spp. (Fossors). They, consequently, sometimes appear veiy 

 prominent and convex in the frontal view ; sometimes they 

 approach very near to each other at the top of the head 

 (making the so-called " frons " or forehead much narrower 



