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 



Fig. 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 JKelliferce (see fig. 2) ; since then I 



have discovered, on the inside of the front tibiae — "" "~ ^*~ *=^J 

 of Bo?nbus, a series of hairs, which also have Fig. 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 



C ^IIZ^ these forms of hairs are useful for clean- 



Fig. 3. ing purposes, and that the directions of 



movement in the front tibise are such that they bring the lateral edges 

 of the hairs into use, whereas those of the posterior tibise 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 Hymenopterists know well the scale-like hairs which clothe 

 the abdominal bands of some of the European species of Ccelioxys, and 

 the thorax of Andrena squaniea, &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 caudata, 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 : 

 Wh December, 1880. 



