A. C. E. MERLIN ON THE FOOT OF THE HOUSE-FLY. 147 



After carefully studying a fine specimen of the house-fly's foot, 

 mounted in balsam, with a Powell and Lealand -^ oil immersion 

 of 1*28 N.A., I have come to the conclusion that the tenent hairs 

 of the pulvillus show a marked appearance of being hollow or 

 tubular, but it is difficult to decide whether the appearance is a 

 mere optical effect or real. 



