372 ORDERS OF PTILOTA. 



which is elongated, and forms, together with the lower jaws, 

 a kind of tongue or sucker, capable of being extended to a 

 considerable length, and employed in collecting honey from 

 flowers ; the females are furnished with a horny apparatus 

 at the extremity of the body, which in some species is 

 transformed into a pair of saws, adapted for making slits in 

 twigs of plants, for the reception of the eggs, and in the 

 others consisting of a powerful sting, the structure of which 

 is already described in page 375. In others, again, it is 

 elongated into an ovipositor, adapted for depositing the 

 eggs in the bodies of caterpillars, &c. The head is fur- 

 nished, moreover, with a pair of antennae, which, in the 

 typical division, consist of thirteen joints in the males, 

 and twelve in the females : in the rest the number of the 

 joints varies in the greatest degree, in some consisting of 

 only five or six, and in others of sixty or seventy articula- 

 tions. In the form of these organs we also find great varia- 

 tion, the sexes difi'ering in this respect, in some being long 

 and slender, in others short and clubbed ; in some furnished 

 with hairs, in others branched or forked, and in the majority 

 ell)ow^ed at the extremity of the basal joint, which is ordi- 

 narily long. The eyes are large, and occupy the sides of the 

 head ; they are alike in both sexes, except in a very few in- 

 stances, in which they are united in the males on the crown 

 of the head, as in some of the Diptera : they are generally 

 round or oval, whilst in some, as the wasps, they are kidney- 

 shaped. They are asserted to be obsolete in a few species of 

 ants. In addition to these composite eyes, the majority of 

 the insects of this order are fm-nished with three minute 

 simple eyelets (ocelli), on the crow^n of the head ; the lower 

 jaw and lip are furnished with palpi, which vary in the num- 

 ber of their joints from six to one. 



The thoracic segments are imited into an oval mass, in 

 the front of which is to be observed an arched piece, termed 



