54 
BRITISH BEES. 
Sometimes a late autumnal impregnation takes place, 
for the males of some Andrence, Halicti, and Bombi are 
found abroad only late in the autumn, and then in fine 
and recently disclosed condition. 
It is a singular circumstance in the history of some 
species, that where they abound one season, nidificating 
on a certain spot in profusion, the following year, per¬ 
haps, and the year succeeding that, they will not be seen 
at all, but yet again a further year, and there they are 
as innumerable as ever. 
What may control this intermittent appearance it is 
impossible to conceive, all the conditions of the spot and 
its surroundings being the same. This I have found to 
be a peculiarity incidental to many of the aculeate Hy- 
menoptera . It occurs also in the flowering of many 
plants which blossom irregularly from season to season. 
It is a fact scarcely concordant with the observed rapi¬ 
dity of the disclosure of the larva from the egg, and the 
speedy growth, development, and transformation of the 
latter into the pupa and imago. 
The wild bees appear to be of annual, or of even more 
restricted duration merely. Of this, however, we have 
no certainty. The conclusion is derived chiefly from 
the circumstance that, as they progressively come forth 
with the growth of the year, they, when first appearing, 
are in fine and unsoiled condition. There are evidently 
in some species two broods in the year; the one in the 
spring and the other autumnal. In bees without pu¬ 
bescence we have not the same guide. But humble-bees 
are reputed to have a longer life than of one year, and 
hive bees are said to survive several years, a duration of 
existence inconsistent with analogy, and which has been 
repeatedly and strongly denied. 
