MEGACIIILE. 
271 
The males of the first division differ in having the 
head slightly larger and squarer above; the antenna 
very slightly longer; the mandibles more acutely tri- 
dentate, with a distinct powerful basal tooth beneath, 
terminating the concavity of the organ; the anterior 
femora, tibia, and joints of their tarsi, excepting the ter¬ 
minal one, concavo-convex, the four first joints of the 
latter distended laterally, and edged with a dense fringe of 
setae, the distension of these joints is widest at their arti¬ 
culation with the tibiae and they decline in length to the 
claw joint which is long; the claws bifid; the interior 
claw acute, but remote from the apical one; the posterior 
femora are very robust, their tibia much curved, robust, 
almost triangular, and externally very convex; their 
planta almost glabrous, not so long as the three follow¬ 
ing joints, externally rather twisted, and beneath fur¬ 
nished with a dense brush of long stiff hair. 
In the second division of the genus the males are des¬ 
titute of the distension of the anterior tarsi, these being 
instead densely fimbriated externally; the legs in them 
are much less robust, and more closely resemble those of 
their females. 
native species. 
§ Anterior tarsi of males much dilated. 
V 
1. Willughbiella, Kirby, $ ?. 5-7 lines. 
2. maritima, Kirby, f ? . 6-7 lines. (Plate XII. 
fig- 2 c? ? •) 
3. circumcincta, Kirby, <$ ? . 4J-5| lines. 
§§ Anterior tarsi of males not dilated. 
1. ligniseca, Kirby, $ $ . 5-7 lines. 
* 2. centuncularis, Linnseus, <$ ? . 4-6 lines. 
centuncularis, Kirby. 
