167 



SUPPLEMENTARY NOTE ON THE FOOT OF THE 



HOUSE-FLY. 



By A. A. C. Eliot Merlin, F.R.M.S. 



{Read November lHth, 1904.) 



With reference to lny note on the foot of the house-fly, read 

 January 15th, 1897 (see Journal of the Qicekett Microscopical Club, 

 Ser. II., Vol. VI., p. 348), I have now to announce a small 

 further advance towards the elucidation of the ultimate structure 

 of the tenent hairs. 



The fuchsin-stained preparation referred to in my previous 

 communication on the subject was especially made with the 

 object of discovering, if possible, the orifice from which exudes the 



4 



6. 



viscous fluid which may be seen adhering to, and often entirely 

 enveloping, the sickle filament ; but no sign of any such opening 

 or vent in the terminations of the hair was at the time detected 

 with the optical means then employed — i.e. a good achromatic 

 oil immersion T V in. by Powell, of N.A. 1*27. Quite recently, 

 however, the identical preparation was again subjected to careful 

 scrutiny under a very fine Zeiss apochromatic \ in., of N.A. 

 1*425, used with a 40 compensating ocular, thus giving a magni- 

 fication of 3,200 diameters. The terminal filaments were perfectly, 

 cleanly, and sharply pictured with this great power, and the 

 existence of a knob or protuberance on the side of the sickle was 

 clearly revealed. 



The above six figures are diagrammatic representations of 

 filaments, Nos. 1, 2, and 3 showing the excrescence which pro- 

 trades from the side of the sickle just mid- way between the 



