lis SELECTED NOTES FROM 



it is very easily worked by putting the bottle in hot water. 2. That 

 it sticks well. 3. That it is almost transparent. For fluid mounts 

 and glycerine jelly, I use Bell's cement, which answers very well, 

 but I always finish off with a coat of coaguline. 



■ — AV. Sargent, Jun. 



Pitchstone, from Arran, is a very remarkable rock which forms 

 veins and dykes intruding amongst the sandstones of the Island. 

 It varies in colour, and also in its contents, but speaking generally, 

 it may be described as a clear glassy base, which has been consid- 

 ered to be a vitreous state of Felsite rock. 'I'his base is densely 

 crowded with minute crystals (Belonites, or Trichites) of Pyroxene 

 or Angite. These are sometimes straight needles, but are also 

 frequently disposed in beautiful fern-like groups. Besides these 

 Belonites, the base also sometimes encloses crystals or granules of 

 Quartz, also crystals of Sanidine, and laminae of Mica, together 

 with strange little balls of Felsite (?) J. M. Mello. 



Feet of Fly. — I believe it to be an established fact that flies' 

 feet are not suckers, but merely what they seem to be — brushes, 

 the hairs of which give out a liquid. However, neither the experi- 

 ment with powder, nor the fact that if you breathe on glass, a fly 

 cannot walk on it because of the moisture, appear to prove to me 

 that the pads are not suckers. Supposing that they were suckers, 

 I think that just the same effects would be produced. Mr. Black- 

 wall's statement (if true, which cannot be doubted) proves the fact 

 that the hairs exude moisture. He says, that if the " track " made 

 by a fly on a piece of glass be examined with a high power, foot- 

 prints (so to speak), formed by moisture, may be detected. Of 

 course, if a fly leaves moisture behind it, it must have exuded it, 

 and, as far as I see, there is no need for this fluid to be glutinous. 

 If merely viscid like glycerine or oil, it would stick just as well. 

 Let any observer try to remove one piece of wetted glass from 

 another, by pulling it away in a direction perpendicular to the sur- 

 face, it will require very considerable force to remove it ; but let 

 him lift up one end first, and it can be done with ease. 



H. M. J. Underhill. 



Hind Leg of Ailantus Scrophulariae, one of the common 



green Sawflies. — This slide has been sjiecially prepared in further- 

 ance of the discussion on the Feet of Flies. The foot has not 

 been treated with Liq. Potass?e, therefore, it retains its natural appear- 

 ance to a considerable degree, and has not even lost its original 

 green colour. In order to get a correct idea of insects' feet, they 

 should be examined dry ViXid fresh from t/ie insect, or mounted in 

 fluid without treatment by alkali. Liq. Potassa^ dissolves out some 

 of the essential parts, and balsam gives the pads the appearance of 



