262 
BRITISH BEES. 
b. With two sulmarginal cells. 
Genus 17. Stelis, Panzer. 
(Plate XI. fig. 3 c? ? .) 
A ns ## c, 1 (3, Kirby. 
Gen. Char.: Body glabrous, much punctured. Head 
transverse, curving posteriorly to the thorax, where it is 
angulated laterally; ocelli in a triangle at the summit 
of the vertex; antenna, short, slender, filiform, scarcely 
geniculated, the scape about as long as the three first 
joints of the flagellum, all the joints of which are sub¬ 
equal but slightly increasing in length towards the apical 
one, which is a little compressed laterally; face entirely 
flat; clypeus transverse, rather convex ; labrum elongate, 
convex; mandibles robust, tridentate, the external tooth 
considerably the stoutest; cibarial apparatus long, tongue 
three times as long as the labium, slightly inflated in the 
centre, and terminating in a small knob; paraglossa 
very short, not more than one-sixth the length of the 
tongue and acuminate; labial palpi about two-thirds 
the length of the tongue, the two first joints membra¬ 
nous, the basal one the most robust, and both tapering 
to an acute apex, shortly before which the two very short 
subclavate terminal joints articulate; labium about one- 
third the length of the tongue, its inosculation trifid, 
the central division considerably the longest and trun¬ 
cated at its extremity ; maxilla subliastate, nearly as long 
as the tongue, acutely acuminated towards their apex; 
maxillary palpi very short, two-jointed, the basal joint 
subclavate and slightly the longest, and inserted in a 
circular cavity, the terminal joint short ovate. Thorax 
subglobose ; prothorax inconspicuous; mesothorax very 
convex ; scutellum lunulate, very gibbous, and impending 
