202 
February, 
^ 
fig. 1. I think this experiment is interesting, as it seems 
to me that a character which is so well sustained, that it 
*ig- i. exists even in the minute hairs of the eyes, ought to be 
one of considerable importance. 
In the same paper I also drew attention to certain hairs with 
dilated apices, and sharp apical edges, which occur on the inside of 
the posterior tibiae of Andrena, and, as far as I have been able to make 
out, of all the Melliferce (see fig. 2) ; since then I 
have discovered, on the inside of the front tibiae 
of Bomb us , a series of hairs, which also have Pig- 2. 
sharp edges, but in these the edge is lateral, and not apical (see fig. 3). 
I think there can be little doubt that both 
these forms of hairs are useful for clean- 
Pig- s. ing purposes, and that the directions of 
movement in the front tibiae are such that they bring the lateral edges 
of the hairs into use, whereas those of the posterior tibiae bring the 
apical edges. I have only as yet found these sharp-edged hairs on 
the Melliferce , and, therefore, I think it probable that they are in some 
way specially adapted for the removal of the pollen-grains. A portion 
of the inner side of the front tibia of a Bombus , showing all the knife- 
like hairs in rows, is a most interesting object for the microscope. 
Many Ilymenopterists know well the scale-like hairs which clothe 
the abdominal bands of some of the European species of Coelioxys, and 
the thorax of Andrena squamea , &c. ; these I have examined with a 
good deal of care, in order to see if I could find anything that could be 
called a true scale. Those which seem to approach most nearly to it 
are the scale-like hairs of Coelioxys caudal a , but the scale-like appear- 
ance is only caused by the very close proximity of the branches, so 
that under a strong power the hair looks somewhat like a short fox’s 
brush : in some the midrib is wide, and one can quite imagine that it 
might become so flattened and wide, as to bear all the branches on its 
dorsal surface, in which case we should get a hairy scale, but as yet 
I have found nothing of the sort, except in imagination. Unfortunately, 
I have very little time for microscopic study, as I am sure that 
attention to the subject of hairs generally, would repay any one who 
has the time and opportunity at his disposal. 
Holmesdale, Upper Tooting : 
4 th December , 1880. 
