14 Proceedings 
in the same way as Chrysis ignita, a well-known parasite ; 
and then we have the evidence of several trustworthy ob- 
servers, that certain species of Sphecodes are always found 
associated with certain species of Halictus. S. pilifrons 
and A. leucozonius, S. similis and H. notatus, S. spinulosus 
and H. nanthopus, are mentioned as occuring together, or 
being alike absent from certain definite localities. For 
my own part, though the evidence is very strong against 
Sphecodes, 1 consider the case as yet ‘not proven.” That 
they are found together in mixed colonies is only what 
might be expected from two genera of similar habits. Both 
Sphecodes and Halictus are found in places where their 
small burrows can be made with facility, and in places that 
are somewhat protected from the cold winds of early spring, 
and which receive all the sunshine possible at that time of 
the year, when the hibernated females of both genera 
appear. That they are destitute of the usual pollen-col- 
lecting organs is not in itself any proof, as they also absent 
in Prosopis, which is now known to construct it own cells. 
Moreover, Dr. Sichel, of Paris, states that Sphecodes carries 
pollen on the head and clypeus, and also that it discharges 
honey. The variation in size is not peculiar to inquilines, 
as it occurs to a very large extent in males of the genus 
Andrena. The peculiar sneaking behaviour of Sphecodes, 
and its association with particular species of adictus, are, 
I think, the two strongest points in the evidence against 
Sphecodes. 
Our largest genus of British Bees, to which about a 
quarter of the total number belong, is Azdrena. It 1s al- 
most world-wide in its distribution, extending from Lap- 
land to New Zealand, but unknown from South America. 
Many species of Avdrena are amongst our earliest spring 
Bees ; A. Clarkella 1 have taken as early as the 19th of 
February. Some of them form very extensive colonies 
while others are more solitary in their habits. They burrow 
into the ground, sometimes in a bank, but often in a hard 
pathway, to a depth of from six to ten inches. Each bur- 
row is said to have short ones branching from it, but some 
that I have examined have apparently been quite simple. 
