HYMENOPTERABEES 



151 



the maxillae {la), the maxillary palps {pm), and the labial palps (//) are also 

 turned downwards and backwards, and the mandibles {md) are brought together 

 over the bases of these parts, at the same time overlapping the downwardly folded 

 labrum (Fig. 64, 2, Ibr) and the retracted ligula (//'). In the state of rest the mandibles 

 alone retain their position unchanged, and are able, without alteration in the position 

 of any other mouth-part, to open and close like the sides of a pair of tongs, i.e. they 

 can bite. When they separate (Fig. 64, 2), the labrum {Ibr), ligula {li), the bases 

 of the backwardly turned laciniae (Fig. 64, 2 b, la), the maxillary palps, and the labial 

 palps become visible. 



Should the bee wish to cease biting and begin to suck nectar, it extends the 

 laciniae, maxillary palps, and labial palps forwards, and spreads out the ligula 



/^ // ^ 



Fig. 64. Mouth-parts of Prosopis (after Herm. Miiller). (i) Head with mouth-parts completely 

 apposed, seen from below. (2) Anterior parts of the same with the mandibles separated, and the labrum 

 turned up. (2 5) Mouth-parts in the same position, more highly magnified. (3) Mouth-parts, after the 

 elevation of the maxillae and the maxillary and labial palps, and with the ligula partly extended ; 

 magnified as in (2b). (4) Ventral view of the front part of the head with mouth-parts fully extended; 

 magnification as in (i) and (2). (4 b) The completely extended mouth-parts ; magnified as in (2*) and (3). 

 Ibr^ labrum (upper lip); md, mandible (upper jaw) ; c, cardo (basal joint of the maxilla or lower jaw); 

 St, stipes (stem of the maxilla) ; la, lacinia ibiade of the maxilla) ; pnt, palpus maxillaris (maxillary palp) ; 

 mt, raentum (chin) ; li, ligula (tongue) ; pa, paraglossae (accessor^' tongues) ; pi, palpus labialis (labial 

 palp) ; o, eye. 



(Fig. 64, 3). It then rotates the cardines of the maxillae (Fig. 64, 4, cc) to the front, 

 and this protrudes the maxillae and labium (mentum and ligula) about twice the length 

 of the cardines, so that the ligula can be inserted into nectar receptacles which are 

 not too narrow or too deep. 



