Prosopis INSECTS. Andreka. 193 
labour is then repeated until she has furnished six or 
eight cells, when the whole is completed.” There is 
little doubt that the same bee constructs more than 
one of these tubes, as there is never any trace of a 
second tunnel running into the first, as in many other 
solitary bees. 
These bees are liable to the attacks of two parasites, 
one of which feeds on the larvae, while the other eats 
the pollen. The first is a fly {Millogramma punctata ) ; 
this fly may frequently be seen entering the cells of 
the bees, and indeed it has been often bred from the 
cocoons of the Colletes. The second enemy is a little bee 
{Epeolus variegatus). The greatest enemy of these 
bees, however, is the earwig, which commits wholesale 
slaughter on them, devouring pupae, larva, and pollen, 
and in some localities they abound to such an extent 
that three-fourths of the bees perish from their attacks. 
The type of the genus Colletes is the C. succincta, a 
species which seems to be very partial to the flowers 
of the heath. 
Genus Prosopis. — At one time the bees of the 
genus Prosopis were thought to be parasites, because 
they wanted the usual apparatus for collecting pollen. 
Mr, Thwaites, in 1841 found two of the species breed- 
ing in bramble- sticks, and since that time others have 
repeatedly bred the species from a similar nidus. Mr. 
Sidney Saunders has observed in Albania a species 
which constructs its cells in bramble-sticks, and lines 
them after the manner of Colletes with a thin trans- 
parent membrane, able to hold a semi-liquid honey, 
which they store up for their young. This species was 
much subject to be infested by a species of Stylops. 
The species of this genus found in the British islands 
are nine in number, and are very partial to the flowers 
of the wild mignonette {Reseda luteola). In this genus 
the body is smooth and naked, and there are only two 
complete submarginal cells : the ocelli are arranged in 
a triangle. The last two genera belong to Westwood’s 
sub-family, called from the bluntness of the tongue 
Obtusilingues. To his sub-family with a pointed tongue, 
and called in consequenceMcMfoYfrepwes, belong the other 
British genera of the family Andrenidm^ of these we 
may specify some of the genera. 
Genus Sphecodes. — The bees of the genus »Sy>^eco(fes 
have no pollenigerous organs; they have four submar- 
giil^l cells to the fore wings, and the antennse are nodose 
in the males. It is doubtful if this genus is parasitic, 
notwithstanding the structure of the feet of the female. 
Genus Halictus. — Twenty-six species of the genus 
Halictus have been described as indigenous to these 
islands ; one of these is the smallest bee found in this 
country, the male being only two lines in length. This 
species is aptly called Halictus minutissimus. The 
species are widely distributed, being found in every 
quarter of the globe. The females of Halictus, and of 
the last recorded genus, make their appearance in April, 
and are to be found from that time until late in the 
autumn, and no males of these genera appear until 
long after the females. The following observations 
have been made on a colony of Halictus Morio, one 
of the most common species, frequently found in path- 
ways in the suburbs of London. The females appear 
early in April, and continue in numbers up to the end 
Von. II. 8 1 
of June. During the month of July scarcely an indivi- 
dual is to be found. About the middle of August the 
males begin to come forth ; the females succeed the 
males in their appearance about ten or twelve days. 
The following appears to be the history of Halictus : the 
males and females appear in autumn ; the impregnated 
females pass the winter in the perfect state, appearing 
during the following season to perform their economy, 
the males not appearing before the autumn, so that in 
their economy they resemble humble bees and wasps 
rather than solitary bees. 
In the genus Halictus the fore-wings have three sub- 
marginal cells ; the abdomen of the females has a ter- 
minal slit. The central division of the labium is longer 
than the external, and in the males the antennse are 
sometimes as long as the bod}'. 
Genus Andrena. — The genus Andrena contains the 
largest number of species of all the British genera. The 
venerable Kirby first greatly enlarged the genus Apis, 
and divided it into sections, each of which was named 
with a generic title by Fuhricius or Latreille. They 
took generally Kirby’s characters, and merely gave 
names.* Sixty-eight species of Andrena have been 
described. The bees of this genus may be truly said to 
be the harbingers of spring, as males may be found on 
catkins and early spring flowers on the first fine April 
days — two species (H. bicolor and A. Gwynana) as 
early as March. The Andrena. are all burrowers in 
the ground, some species preferring banks of light earth, 
while others prefer hard-trodden pathways. The bur- 
rows vary in length ; they are seldom less than six 
inches, whilst others excavate tunnels in the ground 
from nine to ten inches in length. At the bottom 
of each burrow they form a small oval chamber, in 
which the female lays up a small pellet of pollen mixed 
with honey. These pellets are generally about the 
size of a pea, varying in size in the different species. 
The bee sometimes constructs branch tunnels, with a 
similar chamber at the end. When the egg is depo - 
sited, the female bee closes the mouth of the tunnel. 
The species of Andrena are subject to the attacks 
of various parasites. The bees of the genus Nomada 
are parasites, and appear to be on a perfectly friendly 
footing with the industrious bees, being permitted, with- 
out let or hindrance, to enter their burrows. It has 
been advanced as a proof of the ingenuity and artifice 
necessary to be employed in effecting the deposit of 
their eggs in the working bees’ nests, that the parasites 
should bear a close resemblance to the bees on which 
they are parasitic. Some instances may undoubtedly 
be advanced, as Apathiis and Bombus, and also in the 
different species of Volucella which infest the nests of 
humble bees; but amongst the solitary bees there are 
no such resemblances to aid in any necessary decep- 
tion. It may be remarked that the two cases are not 
analogous, and I am not prepared to say that in the 
case of the Bombi and their enemies it may not be 
necessary ; but as regards solitary bees it certainly is 
not — colonies of Andrenidse and their parasites mingle 
* I might have quoted from Kirby, but prefer going to Mr. 
Smith’s volumes, with the great additional information on the 
bees that has been collected since the publication of Kirby’s 
volume. 
