HYMENOPTERA — ANDRENIDE. 265 
One species, H. dilatatus X., has the basal joint of the antenne greatly 
dilated. 
The species of Colletes, of which the type is Réaumur’s ‘ Abeille 
dont le nid est fait d’especes de membranes soyeuses ” (Mém. tom. vi. 
m. 5.), are workers, having hairy bodies for the collection of pollen. 
They nidificate in the earth and the softer parts of walls: each nest 
is cylindrical, consisting of from two to four cells placed end to end, 
the bottom of one fitting into the mouth of that beneath it; each cell 
is about one third of an inch long, and one sixth of aninch broad, and 
is composed of several layers of a very thin and transparent membrane 
(how prepared Réaumur could not ascertain) ; in each cell is deposited 
an egg and a quantity of pollen paste, destined for the food of the 
larva when hatched. The history of these insects is contained in 
Réaumur’s fifth memoir of his sixth volume. The perfect insects are 
generally found towards the end of the summer. I have observed 
that they frequent the flowers of the common ragwort. 
The typical species was first noticed in Grew’s Rarities, the nests 
having been found by that author in the middle of the pith of an old 
elder branch. I have found it burrowing gregariously, in considerable 
numbers, in sunny sand-banks at Coombe Wood, in the month of 
July ; and have succeeded in rearing the bees from the larve (fig. 
90. 9—12.) found in the cells. After the insects have become pupz, 
a thin inner lining, of a dark brown colour, is found to have been left 
by the larvee, which, as it exhibits, under a high-powered lens, no 
traces of a thread or silken construction, is most probably composed 
of hardened pollen paste. 
In the second division of the Andrenide (which may be termed 
Acutilingues), the central terminal portion of the labium is acute 
or lance-shaped (fig. 90. 3, 4.); and in some of the latter genera of 
the division, it nearly approximates in its increased length to the 
structure of the same organ in some of the Apide. 
The species of Sphecodes are the only bees in this division which 
are destitute of pollinigerous organs (fig. 90. 14. Sphecodes gibbus ? , 
15. mandible 3, 16. ditto 9, 17. antenna 4, 18. antenna, 19. hind 
leg? ). They are generally black, and destitute of hairs, with the 
abdomen of a shining red colour. According to M. Walckenaer, they 
are parasitic upon the species of Halictus. Mr. Kirby, however, 
(citing Réaumur’s tom. vi. mém. iv.), states that they make their own 
nests in the manner of the Halicti; but from the construction of their 
