INSECTS IN RELATION TO PLANTS 2 29 



upward movement of the auricle: Further details are given by Casteel, 

 whose admirably precise and thorough studies on the manipulation of 

 pollen and wax by the honey bee have corrected certain prevalent 

 errors and added much to our knowledge of the subject. Arriving at 

 the nest, the hind legs are thrust into a cell and the mass of pollen on 

 each corbiculum is pried out by means of a spur situated at the apex 

 of the middle tibia (Fig. 267, B, .s), this lever being slipped in at the 

 upper 'end of the corbiculum and then pushed along the tibia under the 

 mass of pollen; the spur is used also in cleaning the wings, which ex- 

 plains its presence on queen and drone, as well as worker, but the pollen- 

 gathering structures of the hind legs are confined to the worker. 

 The so-called wax-pincers of the hind legs (Fig. 267, A, C, w) at the 

 tibio-tarsal articulation, have nothing to do with the transfer of wax 

 scales from the abdomen to the mouth, according to Casteel; a wax scale 

 being removed from its pocket by becoming impaled on stiff spines 

 at the distal end of the inner face of the planta. 



For cleaning the antennae, a front leg is passed over an antenna, 

 which slips into a semicircular scraper (Fig. 267, D, a) fashioned from 

 the basal segment of the tarsus; when the leg is bent at the tibio-tarsal 

 articulation, an appendage, or velum (v) of the tibia falls into place to 

 complete a circular comb, through which the antenna is drawn. This 

 .comb is itself cleaned by means of a brush of hairs (b) on the front margin 

 of the tibia. A series of erect spines (sp) along the anterior edge of the 

 first tarsal segment is used as an eye brush, to remove pollen grains or 

 other foreign bodies from the hairs of the compound eyes. The labium 

 and maxillae (Fig. 56) are exquisitely constructed with reference to 

 gathering and sucking nectar; the maxillae are used also to smooth the 

 cell walls of the comb; the mandibles (Fig. 56, md), notched in queen 

 and drone but with a sharp entire edge in the worker, are used for cut- 

 ting, scraping and moulding wax, as well as for other purposes. The 

 entire digestive system of the honey bee is adapted in relation to nectar 

 and pollen as food; the proventriculus forms a reservoir for honey and 

 is even provided at its mouth with a rather complex apparatus for strain- 

 ing the honey from the accompanying pollen grains, as described by 

 Cheshire. The wax glands (Fig. 104) are remarkable specializations in 

 correlation with the food habits, as are also the various cephalic glands, 

 the chief functions of which are given as: (i) digestion, as the conversion 

 of cane sugar into grape sugar, and possibly starch into sugar; (2) the 

 chemical alteration of wax; (3) the production of special food substances, 

 which are highly important in larval development. 



