24 BEHAVIOR OF HOSTEY BEE IN POLEEX 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 humblebee the 
tongue is longer, and it could more easily moisten the hind legs in 
the way suggested." 
In an earlier paper Sladen (1912, a) gives 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 polleu-collectiug 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, <~) 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 grains 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 bj 
Cheshire. 
