72 THE HUMBLE-BEE 111 
prey on the Loméz, It is a remarkable fact that 
the sting of the ¢evrestrzs queen differs from that 
of the Jducorum queen and approaches that of 
Psithyrus in being somewhat stouter and more 
curved, and having its thickened basal portion more 
parallel-sided when viewed sideways than in ducorum. 
There is, however, no evidence to show that any 
species of Pszthyrus has sprung from the particular 
species of Bombus on which it preys, such resem- 
blances as it may show to it in coat-colour, etc., 
being pretty clearly attributable to mimicry or 
exposure to the same conditions of life, and not to 
ancestry. 
The males of the Pszthyrt are very fond of 
drowsing on flowers, especially on the heads of the 
knap-weed ; they are even more fragrant than the 
males of the Bomdéz. In their play, which is probably 
amorous, they hover over meadows and grassy 
slopes. I know two exposed grassy inclines, both 
facing north-west and having no trees near, where, 
every August, the males of Ps. rupestris may be 
seen flying about, skimming the grass, sometimes in 
considerable numbers. I have seen the males of 
Ps. barbutetlus hovering over the grass in the same 
way in July, but in the vicinity of trees. 
I have dug up the hibernating queens of Ps. 
vrupestris, vestalis, barbutellus, and campestris from 
banks facing north-west, occupying little cavities in 
the ground, about two inches below the surface, 
exactly like the queens of ZB. dapzdarzus and other 
Bomot. 
