HYMENOPTERA. ACULEATA. 227 



yellow or cream-coloured markings on the face (whence 

 perhaps its name), on the thorax, and on the legs. They 

 are from one-eighth to a quarter of an inch long; the 

 wings have two subraarginal cells. 



The remaining six genera of short-tongued Bees have 

 these organs pointed and more or less tapering. 



The first genus, Sphecodes, consists of small Bees 

 from one-eighth to half an inch in length, easily re- 

 cognised by the absence of pollen-bearing organs and 

 sphex-hke colouring of their shining red and black bodies, 

 the thorax being black and the abdomen brownish red 

 (see PL IX., fig. 1, S. ruf.), sometimes tipped with black. 



The Sphecodes are gregarious and frequently choose 

 the same ground for their burrows as Hal-ictus, the 

 second genus of the sharp-tongued Andrenidae ; from 

 this circumstance, and from the absence of visible 

 means of carrying pollen they, like Prosopis, have 

 been supposed to be parasitic. This, however, has been 

 disproved by the observations of Mr. Smith, who not 

 only saw the female Sphecodes at work upon her burrow, 

 but found that the burrows entered by Sphecodes in a 

 mixed colony were too small to admit the female of the 

 Halictus. 



The Sphecodes are black and red, and shining. The 

 species, of which there are five, vary in size from one- 

 twelfth (!) to half an inch. The submarginal cells are 

 three in number. 



The Halictus, gregarious, as its name indicates, 

 forms burrows in the earth, in which several tubes open 

 into one common entrance. These contain the eggs, and 

 are stored with food as in other cases. This genus also 

 contains some of the smallest Bees known, the $ of H. 

 minutissimus is sometimes no more than one-eighth of an 



Q 2 



