66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3 



pressure because of a small process of the tibia (/) that abuts against 

 its base. The antenna is thus held securely and is now drawn upward 

 through the cleaner, the tarsal comb brushing its sensory outer sur- 

 face, the thin lobe (jf the filiula scraping its inner surface. 



The antenna cleaner is not a gadget peculiar to the bees ; it is 

 developed in some measure in most of the clistogastrous Hymenoptera 

 (fig. 14, F, G, H, I), though the tarsal notch is usually shallower than 

 in the honey bee, and may be but a sinuosity of the tarsal margin. 

 The fibula of the cleaner is simply a special development of an or- 

 dinary movable spur usually present on the end of the tibia, such 

 as is present on the middle leg of the adult bee (fig. 22 A, B), and 

 also on the hind leg of the pupa. 



The middle legs. — The second legs are the least specialized of the 

 legs in the bee, and have the simplest form in the drone (fig. 22 A). 

 In each caste the end of the tibia is armed ventrally with a long spine, 

 which has been said to be used by the worker for removing wax 

 from the wax pockets of the abdomen, but the evidence of such use 

 of the spine has been questioned. The basal tarsomere is long and 

 cylindrical in the drone (A), in the worker and queen it is wide and 

 flattened, in the worker (B) its under surface is thickly covered with 

 long stiff hairs projecting distally, and serves as a pollen brush. 



The hind legs. — The large hind legs are the most specialized in 

 form of all the legs by reason of the great size and lateral flattening 

 of the tibia and basitarsus (fig. 23 A, F, H). Though this feature 

 is common to the three castes, a functional reason for it is not evident 

 except as it is elaborated for useful purposes in the worker. The 

 femur has a coating of small hairs in the drone (F), in the queen and 

 the worker (A) it is bushy with long feathery hairs. The tibia of the 

 drone (F), aside from its size and shape, has no special characters; 

 in the queen (H) the tibia is relatively wider and thick at its base; 

 in the worker (A) it is narrowed proximally and expanded distally, 

 and its smooth, somewhat concave outer (anterior) surface (C) is 

 bordered with long curved hairs, forming the pollen-carrying basket, 

 or corbicula. The basitarsus is equally large in each caste (A, F, H), 

 but there is no apparent reason for its size and shape in the queen and 

 the drone ; the cavity of the basitarsus is traversed by the tendon of 

 the pretarsal claws and is otherwise occupied only by a loose mass of 

 fat tissue. In the worker the inner (posterior) surface of the basi- 

 tarsus (A, Btar) is armed with about 10 transverse rows of long, 

 slender spines directed mesally and distally at an angle of 45°. The 

 basitarsus of the worker thus resembles a flat brush or currycomb, 

 and has been termed the strigilis (Betts, 1923), though the same 



