228 HYMENOPTERA ACULEATA. 



Several species used to exist iu our list characterized only 

 by the effects of stylopization. Many of our species are 

 double-brooded, occurring in early spring and again in July 

 or August. In some cases the autumn brood slightly differs 

 from the spring one, especially in the $ sex. The species 

 of Jndrena often form colonies, sometimes extensive ones, 

 generally in banks or pathways, or often on commons 

 amongst the grass, &c. Most of the species occur in the 

 spring, and are partial to the flowers of Salix; after these 

 Lave died off, dandelions, bryony, blackberry, and other open 

 flowers whoso honey sbort-tongued bees can reach, attract 

 them. The males do not always occur with the females, al- 

 though they are probably flying about near the flowers which 

 they frequent, they much less rarely settle, and are often 

 very difficult to catch, especially when coursing up and down 

 a hedge as they often do. Smith says that their burrows 

 vary from about six to twelve inches in depth, and that the 

 cells, with the exception of the terminal one, are placed in 

 short branches from the main stem. Many of the species 

 of this genus are attacked by the inquiline genus Nomada, 

 ■which lays its egg by the side of that of the Andrena, and 

 its larva consumes the food stored up by its host, and comes 

 to perfection in its stead. There is another little creature 

 often found on species of this genus, viz. the larva of Meloe. 

 In its very early stages it is a little elongate yellow, or 

 more rarely black, hexapod with long caudal setae, but 

 it does not seem to affect the And.rena injuriously. 



Altogether there are forty-eight British species, and the 

 number of known species is quite problematical. The 

 genus is one of very wide distribution, but seems to be 

 chiefly found in temperate regions. 



It is necessary to warn collectors against mistaking the 

 colour of the pollen on the scopie for the colour of the 

 scopse themselves. 



(S) 1. Basal area of propodeum clathrately 

 rugose, bounded by a raised line ; ab- 



