24 BEHAVIOR OP HONEY BEE IN POLLEN COLLECTING. 



(planta) and that it might rub over the brushes of the metatarsi 

 or be caught between them when they are approximated and thus 

 moisten the two brushes simultaneously. However, he has never 

 seen the tongue of the collecting honey bee brought near to the hind 

 legs, and it appears probable to him that it can not easily reach them. 

 " Possibly the middle or front legs are used as agents for conveying 

 the honey" (in the case of the honey bee). "In the bumblebee the 

 tongue is longer, and it could more easily moisten the hind legs in 

 the way suggested." 



In an earlier paper Sladen (1912, a) gjves the following as his 

 opinion of the " way in which pollen dust is moistened with nectar," 

 although he states that this is one of the points " which still remains 

 obscure " : 



The only satisfactory manner In which; it seems to me, this can be done is 

 for the tongue to lick the tarsi or metatarsi of the forelegs, which are covered 

 with stiff bristles, well suited for holding the nectar, the nectar being then 

 transferred to the metatarsal brushes on the middle legs, and from these, again, 

 to the metatarsal brushes on the hind legs. The latter being thus rendered 

 sticky, the pollen dust would cling to them. The different pairs of legs were 

 certainly brought together occasionally, but not after every scrape of the 

 hind metatarsi, and their movements were so quick that it was Impossible 

 to see what was done. Still, several pollen-collecting bees that I killed had the 

 tarsi and metatarsi of the forelegs and the metatarsal brushes of the middle 

 and hind legs moistened with nectar, and I think it probable that the moisten- 

 ing process, as outlined, is performed, as a rule, during the flight from flower 

 to flower. 



Sladen (1912, c) also considers the possibility that the fluid which 

 moistens the pollen might be secreted through the comb at the end 

 of the tibia, through the tibio-tarsal joint, or from the surface of the 

 auricle, but finds no evidence of glandular openings in these regions. 

 A suggestion of a similar nature, apparently unknown to Sladen, 

 was made by Wolff (1873), who describes "sweat-glands" which, 

 he claims, are located within the hind tibia and the planta, and 

 which pour a secretion upon the surface of the corbicula and upon 

 the upper end of the planta through many minute openings located 

 at the bases of hairs, particularly those which arise from the lateral 

 margins of the corbicula. Wolff is convinced that the fluid thus 

 secreted is the essential, cohesive material by which the grains of 

 pollen are bound together to form the solid mass which fills each 

 fully loaded basket. He noticed that the mouthparts are used to 

 collect pollen, and that some of it is moistened with " honey " or 

 " nectar," but he does not consider that the fluid thus supplied is 

 sufficient to explain adequately the facility with which the collecting 

 bee brings together the scattered gi'ains of pollen and packs them 

 away securely in the baskets. Wolff's description of the basket-load- 

 ing process itself is strikingly similar to that advocated later by 

 Cheshire. 



