ANATOMY AND PHYSIOLOGY. 71 
called, by a deep notch on the inner side, just at the 
point where the scape of the antenne lies in front of 
them. In some species of our Vespxe the notch in 
the dark eyes is brought out more plainly by the 
integuments here having a bright yellow colour, and 
in them, all the lower limb of the eye is at least 
edged with yellow. In the Solitary group, as the 
movements of the head are limited by the front of 
the thorax being full and square, to make up for this 
restriction their compound eyes are proportionately 
larger and more prominent than in the Social group, 
where the free movements of the head on the rounded 
thorax give a wide range of vision. There is no 
notable difference in the extent of the compound 
eyes in the sexes of wasps, but in the male of the 
honey-bee they are much larger than in the worker, 
and meet across the vertex of the head, as in some 
of the common flies. 
Between the eyes, separated at their roots by 
the width of the corona, the antenne take their 
origin. They are of the simplest possible form, like 
thick black hairs, hard and polished, and beaded all 
the way down. The number of these beads or joints, 
and their relative size, are points of technical im- 
portance. A long joint, which has already been 
referred to under the name of the scape, begins the 
series. Then comes a very short one, on which the 
antenna generally turns at an angle, is geniculated, 
as it is called. Ten more joints go to make up the 
flagellum or flail; the first somewhat longer than the 
rest. In the males there are eleven joints here, 
thirteen in all. This odd joint is simple, like the 
