THE aXDRENA and HER PAEASITIC BEETLE. 357 



2>EXT comes the typical genus of the family, two examples of 

 which are given on Plate XI. The genus Andrena lias the 

 head as wide as the thorax, and, in the male, occasionally 

 wider. The antennae are elbowed ; the wings have one mar- 

 ginal and three submarginal cells, and the hinder tibiae are 

 furnished with stiff bristles by means of which the insect can 

 carry to its home the pollen which it obtains from flowers. 

 One of these Bees may be seen on Plate XI. Fig. 4. It is 

 called Andrena nitida, from the polished and shining abdomen. 

 The colour is black, the thorax being clothed with yellowish 

 down. The nervures of the wings are rust-red, and there is a 

 darkish clouding at their tips. On each side of the second and 

 third segments of the abdomen is a patch of white down, 

 and the tip of the abdomen has a fin^ dun-coloured fringe. 



This pretty species occurs early in spring, and may be found 

 on the flowers of the common dandelion. It makes a burrow 

 very similar to that of the Halictus, and, like that insect, forms 

 short accessory burrows radiating from the principal shaft. 



Anothek species, Andrena Trimmerana, is seen on Plate 

 XI. Fig. 5. The colour of this Bee is black, the thorax being 

 covered with a reddish-dun down, and the legs being covered 

 with brownish hairs on their upper surface. The antennae of 

 the female are longer than is usually the case. One of its 

 burrows is seen, from which it is just emerging. One of the 

 larvae is shown at Fig. 10. 



This insect is common near London, and is worthy of atten- 

 tion as being often infested with the remarkable little beetle 

 called the Stylops, which has been described on page 157. At 

 Fig. 5 the Stylops may be seen just appearing from beneath 

 one of the segments of the abdomen ; and at Fig. 6, at the 

 top of the Plate, the insect is seen as it appears when flying, 

 the peculiar milkiness of the wings being very well given. 

 The species which is most attacked by the Stylops is Andrena 

 convexiuscula. Out of thirty specimens of this insect, not 

 one had escaped the Stylops. It is found in the Isle of Wight 

 and other places, but does not appear to live near London. 



Of this enormous genus, nearly seventy species are in the 

 British Museum. Some burrow in loose sand, some in hard 

 ground, and some even prefer very hard, strong paths, over 



