HYMENOPTERA—BEES rf I51 
the maxillae (/2), the maxillary palps (fm), and the labial palps (f/) 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, /or) and the retracted ligula (Z’). 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 (dr), ligula (7), the bases 
of the backwardly turned laciniae (Fig. 64, 24, /a), 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 
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Fic. 64. Mouth-paris of Prosopis (after Herm. Miller). (1) Head with mouth-parts completely 
apposed, seen from below. (2) Anterior parts of the same with the mandibles separated, and the labrum 
turned up. (24) 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 (26). (4) Ventral view of the front part of the head with mouth-parts fully extended; 
magnification as in (1) and (2). (4 4) The completely extended mouth-parts; magnified as in (26) and (3). 
lér, labrum (upper lip); 7d, mandible (upper jaw); ¢, cardo (basal joint of the maxilla or lower jaw); 
st, stipes (stem of the maxilla) ; 7a, lacinia (blade of the maxilla) ; 4, palpus maxillaris (maxillary palp) ; 
m#, mentum (chin); 72, ligula (tongue); fa, paraglossae (accessory tongues); #/, palpus labialis (labial 
palp) ; 9, 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. 
