144 HYMENOPTERA. 



neath, and the anterior upper surface of the femora is clothed 

 -with h>ng loose hair, which equally surrounds the whole of the 

 tibijie." (Shuckard.) The abdomen is banded more or less 

 conspicuously Avith reddish. 



The larva (Fig. 80) is stout and thick, with a head of moder- 

 ate size, and the mouth -parts are a little shorter than usual, the 

 maxillae and labium especially. The segments of 

 the body are much more convex (angularly so) 

 than usual, giving a tuberculate outline to the 

 body. It is stouter than that of Halictus, the 

 wings are less convex than in that genus ; while the 

 maxillse are much stouter and blunter. The pupa 

 is distinguished from the other genera by much the 

 same characters as the imago, except that there 

 Fig. 70. j^j.g ^^vo tubercles on the vertex near the ocelli. 

 From a comparison of all its stages, this genus stands inter- 

 jnediate between those placed above, and Halictus, which, in 

 all its characters, is a more degraded form. The males often 

 differ widely from the other sex, in their broad heads and widely 

 spreading bidentate mandibles. 



Mr. Eraerton has observed the habits of our most common 

 species, Andrena vlcina Smith, which builds its nest in grassy 

 fields. The burrow is sunken perpendicularly, with short pas- 

 sages leading to the cells, which are slightly inclined downwards 

 and outwards from the main gallery. The Avails of the gallery 

 are rough, but the cells are lined with a mucus-like secretion, 

 which, on hardening, looks lilvc the glazing of earthen-ware. In 

 Fig. 80 ]Mr. Emerton gives us a profile view of natural size of 

 the nest showing the main burrow and the cells leading from it ; 

 the oldest cell, containing the pui)a (a) is situated nearest the 

 surface, while those containing larviis (b) lie between the pupa 

 and the cell (e) containing the pollen mass and egg resting 

 upon it. The most recent cell (/) is the deepest down, and 

 contains a freshly deposited pollen mass. At c is the begin- 

 ning of a cell ; g is the level of the ground. The bees were 

 seen at work on the 4th of May, at Salem, Mass., digging their 

 holes, one of which was already' six inches deep ; and by the 

 loth, hundreds of holes were observed. On the 28th of May, 

 in unearthing six holes, eight cells were found to contain pol- 



