11 LIFE-HISTORY OF BOMLUS i 
clearing in a wood, near some bushes or trees, one 
is almost sure to see now and then a humble-bee 
fly swiftly by and enter a dark hollow under a tree 
or shrub, where it pauses for a second, almost 
alighting, and then passes out and proceeds to 
another recess, where it again pauses and almost 
alights. Each succeeding bee flies in the same 
direction and visits the same spots. If these bees 
be caught, it will be found that they are all males 
either of B. pratorum or L. hortorum. This strange 
behaviour ot the male humble-bee has puzzled 
many observers, but I have noticed certain facts 
about it that point to an explanation. A sweet 
fragrance, like the perfume of flowers, is perceptible 
about the pausing places. This same fragrance 
may be detected in the scent produced by a male 
if he be caught in the fingers, although it is now 
blended with an odour like that of sting-poison 
emitted in fear. Evidently, therefore, the males 
emit the perfume in their pausing places; and | 
think it extremely likely that in doing so they 
attract not only one another, but the queens. The 
males of the one species do not pause at spots 
frequented by those of the other species, and we 
may infer from this that each species emits a 
different scent. 
The males of all the species are more or less 
fragrant when captured, those of 2. latrezllellus and 
B. distinguendus being especially so. The scent, 
I find, proceeds from the head, probably from the 
mouth. At the end of August 1910, my study 
