NO. 2 HONEY BEE — SNODGRASS 5 



to the worker caste, in which the jaws se^-ve as tools for handhng 

 wax. The ingestion of nectar from the depths of flower corollas or 

 of honey from the cells of the comb, on the other hand, necessitates 

 a special apparatus for reaching the liquid and for drawing it up to 

 the mouth. Hence the principal structural modifications of the feed- 

 ing apparatus affect those parts that contribute to the formation of 

 the proboscis and the sucking pump. These same organs are able to 

 function also in reverse for the regurgitation of nectar and honey. 

 The principal "new" feature in the mouth parts of the bee is the 

 salivary channel of the tongue, but this channel is probably only an 

 elaboration of a groove along the line of union of the glossae. Finally, 

 the need of having the proboscis out of the way when comb-building 

 is in progress, or when the mandibles are otherwise in use, has been 

 met by adaptations in the free parts of the proboscis that enable the 

 latter to be folded and temporarily stored in a receptive cavity on 

 the back of the head, from which the parts can be again extended 

 and reassembled for functional purposes. 



The so-called proboscis of the bee is hardly to be termed an "organ," 

 since as a functional unit it is improvised when the bee would feed 

 on liquids by bringing together the various free parts of the 

 maxillae and the labium (fig. 3 A) in such a way as to form a tube 

 (C) through which nectar, honey, or water may be drawn up to the 

 mouth. When not in use the parts are disassembled and folded back 

 behind the head (fig. 3B), where they are held in place by the 

 mandibles {Md) clasped beneath them. The major parts of the 

 maxillae and labium are adapted in form to the roles they play in the 

 functional position ; the flexing mechanism depends on smaller 

 modifications and minute adjustments between the skeletal elements 

 and certain muscles. All the specialized movements involved in the 

 operation of the proboscis of the bee, however, are produced by 

 muscles that can readily be identified with the usual muscles of the 

 maxillae and the labium in generalized insects. 



The adjustable components of the proboscis are the broad, bladelike 

 galeal lobes of the maxillae (fig. 3 A, Ga), the long labial palpi 

 (LbPlp), and the slender median tongue formed of the united 

 glossae (Gls). When these elements are assembled to form a tube, 

 the galeae and the palpi are brought alongside the tongue and, with 

 the last, enclose a temporary channel. The wide galeae (C, Ga) 

 form the sides of the tube and overlap each other above the tongue to 

 form also the roof; the labial palpi {LbPlp) lie beneath the galeae 

 and close the tube below by underlapping the tongue, while marginal 

 fringes of hairs on the galeae and palpi prevent leakage between 



