BEES OF GREAT BRITAIN. 45 



on the vertex ; the kbial palpi 4-jointed, nearly as long as the 

 labium; the basal joint longest, each gradually decreasing in 

 length ; the paraglossa3 shorter than the labium ; the maxillary 

 palpi 6-jointed, the second joint longest. The superior wings 

 with one marginal and three subraarginal cells; the second 

 submarginal cell receiving the first recurrent nervure in, or about 

 the middle; the posterior femora furnished with a floccus of 

 hairs at the base, and the posterior tibiae and basal joint of the 

 tarsi covered with a thick scopa, or pollen-brush. Abdomen 

 usually elongate-ovate, sometimes ovate; that of the males 

 usually elongate and lanceolate; their mandibles frequently 

 forcipate. 



The bees included in the genus Andrena may be truly said 

 to be the harbingers of spring, for on the first fine days of 

 April males will be found frequenting the catkins and the 

 early flowers of spring ; my earliest date of their ca})ture is 

 March 4th, 1849, when I met with Andrena bicolor and Gwy- 

 nana, both sexes of each. 



This genus is by far the most numerous in species of all the 

 genera of bees found in this country; we have about seventy 

 known species, and when the northern parts of the country 

 are assiduously searched, no doubt many more will be added. 

 These bees are all burrowers in the ground, some species prefer- 

 ing banks of light earth, others hard trodden pathways, &c. ; 

 their burrows differ in depth, but are seldom less than about six, 

 whilst others excavate to nine or ten inches; at the bottom 

 of each burrow is formed a small oval cell, or chamber, in which 

 the industrious female lays up a small pellet of pollen mixed 

 with honey ; these little balls are usually about the size of a 

 garden pea, varying somewhat in size in different species. Some- 

 times, apparently to economise time, the bee constructs branch 

 tunnels, each having a similar chamber at its extremity ; this 

 peculiarity I have observed in A. rubricata and A.fulvescens; 

 it is also probably not unusual with many other species : when 

 she has completed her task, she closes the mouth of the tunnel. 



These bees are subject to the attacks of parasites : the first 

 to be remarked upon, are those bees which compose the genus 

 Nomada ; they are more popularly known as wasp-bees, since 

 they bear a considerable resemblance to some of the small 

 solitary species of that family. These parasites appear to be 

 upon a perfectly friendly footing with the industrious bees, and 

 are permitted, without let or hindrance, to enter their burrows. 

 It has been advanced as a proof of the ingenuity and artifice ne- 



