306 
BRITISH BEES. 
at tlie upper part of Hampstead Heath, to Highgate, from 
which road it was separated by merely a band of whins 
and coarse grass, used to be a very favourite collecting 
place of mine, for there, and in its immediate vicinity, 
I have often caught, within a very brief period, more 
than half the genera, and a very large number of the 
species of the fossorial Hymenoptera. One particular 
little spot was inhabited by Psen equestris, rare every¬ 
where else, and our largest Cerceris , who carried on their 
instinctive pursuits during all the summer months, but 
at a particular time in the autumn, varying slightly 
with the nature of the season, a flock of wagtails ( Mota - 
cilia) would alight and make brief work of those fossores 
which were still aflight; and this was repeated season 
after season, as if the wagtails thought it was time that 
their own rapacity should stop the course of these pre¬ 
dacious insects. But to return, the female Apathi then 
resort to the nests of the Bombi whence they have issued, 
and lay themselves up in their winter dormitory. That 
this must take place speedily after impregnation is ren¬ 
dered almost conclusive by the fine state in which their 
pubescence appears in the spring, which would be tar¬ 
nished did they loiter about visiting flowers previous to 
their return home. But the labours of the female and 
neuter Bombi themselves are now over, and they would 
therefore find no store whereon to deposit their eggs. 
The parasitical allocation of these insects is as follows. 
Apathus rupestris infests Bornbus lapidarius; A. vest alls 
the B. terrestris, and this forms an instance in which 
the parasite is not clothed in the colours of its sitos. 
But A . Barbutellus has a wide range, for it frequents 
the nests of B. pratorum , B. Derhamellus , and B. Skrim- 
shiranus. 
