4. ANDRENA. 21 



considered it to constitute two species, but I have satisfied myself 

 since that it is only a variable insect. In the Linnoean Cabinet it is 

 the authentic specimen of the Sphex ephippia of Linnams, one of 

 the varieties of this insect. The Melitta divim of Kirby is a dark 

 example of the male, having the antennae black, but they are usually 

 more or less fulvous beneath ; but in truth it is almost impossible 

 to decide whether the latter variety be not in reality a very minute 

 male of S. r/iblms. Many of the Ivirbyan specimens preserved in the 

 Entomological Society's Museum are now in a very decayed con- 

 dition. 



Genus 4. ANDRENA. 



Apis (pU, Linn. Syst. Nat. i. 958 (1766). 

 Andrena (pt.), Fabr. Si/d. Ent. 376 (1775). 

 Nomada (pt.), Fabr. Ent. Syst. ii. 345 (1793). 

 Melitta, Kirby, Mon. Apum Anijl. i. 140 (1802). 



Head as wide as the thorax, transverse, in the males frequently 

 wider than the thorax ; ocelli in an isosceles triangle on the vertex ; 

 antennce geniculated, filiform, the basal joint of the nagellum longest; 

 the labium lanceolate, the pararjlossaj more than half its length ; 

 the labial palpi 4-jointed, the basal joint longest, the following 

 joints each decreasing in length ; the maxillary palpi 6-jointed, 

 the second being the longest. Thorax : the anterior tvings with one 

 marginal and three submarginal cells ; the second submarginal recei- 

 ving the first recurrent nervure in or near the middle of the cell, the 

 third submarginal cell receiving the second recurrent nervure beyond 

 themiddle; \\\q posterior trochanters furnished with a long floccous hair, 

 the posterior tibiae and basal joint of the tarsi with a thick scopa or 

 pollen-brush. Abdomen elongate-ovate, the apical margin of the fifth 

 segment and sides of the sixth with a dense fringe of pubescence, 

 the latter segment having a central naked space : the abdomen of 

 the males usually elongate and lanceolate; their mandibles frequently 

 forcipate. 



The bees included in the genus Andrena may be called the har- 

 bingers of spring. One of the first to appear is A. clarkella : this 

 species has been observed as early as March 4th, before the snow 

 had quite melted, and when unusually warm weather had set in ; 

 A. gwynana was found at the same time at Hampstead. The usual 

 time when the Andrenidre make their appearance is April, early or 

 otherwise, according to the suitableness of the weather. 



This genus is the most numerous of all the Apida) in species, and 

 also in the numbers of many of them, colonies of thousands upon 

 thousands being occasionally met with ; they are all burrowers in 

 the ground, some species preferring banks of light earth, others a 

 stiff clayey soil, whilst some choose hard trodden pathways. A few 

 species, and these usually rare, are almost to be classed among the 

 solitary bees ; these I have never found forming colonies, a few 

 burrows scattered at wide distances in a locality heiug their habit. 



