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parts of an insect consist of an upper lip, an under lip, a pair 

 of anterior jaws or mandibles, and a pair of maxillae. The 

 lower lip and maxillae are each provided with a pair of feel- 

 ers or palpi. The mandibles are usually Jiard and horny, 

 while the raaxillise are delicate and membranous. Different 

 insects show great variation in the structure of their mouth 

 parts, even in the same order. Take members of the genus 

 Proiopis which construct their cells in sand and dry sticks, 

 the lower lip is constructed in the form of a trowel. This 

 insect has in fact no special adaptation for eollectinpr nectar. 

 Although these bees feed their young on honey and pollen, 

 they can only obtain nectar in flowers with shallow nectaries. 

 In different bees there are various gradations, as in Andrena, 

 Halictus and Chelostoma. The lower iip becomes variously 

 elongated until it reaches the length and form found in hive- 

 bees and bumble-bees which enables them to extract honey 

 from irregular flowers with deep seated nectar. 



In Bombus the mouth parts consist of ^a, the paraglossa, 

 U, the ligula, pi, labial palpi, ^w, maxillary palpi, la, lamina, 

 mt, mentum, st, stipes, md, mandibles, and o, eyes. When 

 the mouth parts are fully extended and separated it seems 

 hardly possible that this large and complex apparatus for 

 sucking, exceeding in length that of the head, can be 

 received in the cavity below the head, but such is the case. 

 When a bee is sucking honey just within its reach, the car- 

 dines, the chitinous retractors just at the base of the mentum, 

 the laminae, labial palpi and tongue are fully extended. As 

 soon as the whorls of hairs at the point of the tongue are wet 

 with honey, the bee by rotating the retractors (below the sub- 

 mentum) draws back the mentum and with it the tongue, so 

 far that the laminae now reach as far forward as the labial 

 palpi. The laminae and labial palpi now lie close upon the 



