﻿i6 



IIYMENOPTKKA 



invaginated part can be thr 



list out by increase of the pressure of 

 the nuid in the tube. A portion 

 of the wall of the invaginate pari 

 is thickened so as to form a chiti- 

 nous rod. 



This description will suffice for 

 present purposes, as the other parts 

 of the mouth will he readily re- 

 cognised by the aid of figure 9, A. 

 P>, C. In the exquisitely endowed 

 South American genus Euglossa ( Fig. 

 18), the proboscis is somewhat longer 

 than the whole of the body, so that 

 its tip in repose projects behind 

 the body like a sting. 



The correct nomenclature of the 

 parts connected with the lower lip 

 is not definitely settled, authorities 

 not being agreed on several points. 

 The whole of the proboscis is usually 

 called the tongue ; this, however, is 

 admittedly an erroneous application 

 of this term. The terminal deli- 

 cate, elongate, flexible organ is by 

 some called the tongue ; but this 

 again is wrong : the lingua in 

 Insects is the hypopharynx ; this part is developed in a peculiar 

 manner in bees, but as it is not tongue-like in shape, the term 

 lingua is not suitable for it, and should be dismissed altogether 

 from the nomenclature of the bee's trophi ; it is used at present 

 in two different senses, both of which are erroneous. "We see no 

 objection to describing the flexible apical portion of the proboscis 

 as the ligula. The lorum is probably a special part peculiar to 

 the higher bees ; according to Saunders it is not present as a 

 specialised part in some of the primitive forms. 1 The application 

 of the terms mentum, submentum and hypoglottis is open to the 

 same doubts that exist with regard to them in so many other 



Fie;. 8. — Transverse section of ligula 

 of honey-bee, diagramatic. A, 



With the long sac invaginate. B, 

 evaginate : a, chitinous envelope 

 with the bases of the hairs ; 6, 

 rod ; e, groove of rod ; d, lumen 

 due in A to invagination of the 

 rod, in B to its evagiuation ; it, 

 nerve ; tr, trachea. 



1 For figures and descriptions of the proboscides of British bees, refer to E. Saun- 

 ders, Jour. Linn. Soc. xxiii. 1890, pp. 410-432, plates III.-X. : and for details of 

 the minute structure and function to Cheshire, Bees and Bee-kee]ring, vol. i. 



