268 BRITISH BEES. 



entomologist Nylander supposes he has found one in the 

 plates of the apical segment of the abdomen, especially 

 those of the venter, in which he detects both a differ- 

 ence of form and a difference of relative length to that 

 of the superior plates, and in the males he assumes that 

 the teeth of the apical segment are constant characters. 

 Not having had sufficient opportunity since this sup- 

 posed discovery was made, for the examination of a 

 great multitude of specimens, for it is only upoi> such 

 an investigation that it can be firmly based, I cannot 

 speak corroboratively upon the point, but it is very pos- 

 sibly a correct solution of the difficulty. 



The peculiarity of these spines at the apical segments 

 of the abdomen of the males is remarkable, they being 

 straight projecting processes, or they have even a slight 

 upward bearing. In the males of Anthidium and Osmia 

 we observe spines also arming the apex of the last seg- 

 ment, but in these we can trace an evident use, both 

 from the downward curvature of the abdomen itself, and 

 that same tendency also in the spines. But in the in- 

 sects of this genus they have not the same conspicuously 

 apparent object, the abdomen itself even having an up- 

 ward curvature, or rather a greater facility for turning 

 upwards than downwards. These insects appear to be 

 most abundant in the midland and southern counties, 

 and, according to Curtis, they are numerously found at 

 the back of the Isle of Wight. I have usually taken 

 them on the wing and never on a flower, and I do not 

 know the plants which they may prefer. 



