120 SELECTED NOTES FROM SOCIETY'S NOTE-BOOKS. 



Something is then wanted to bind the colour together when dry. 

 Dammar or Canada balsam will do, but neither are so good as 

 Copal varnish. Several kinds of this varnish can be had at the 

 oil and colour shops, but for this purpose it must dry without heat, 

 and be free from colour. That which is known in the trade as 

 La)/ip-hcad vvccmsh. is the best, it dries in about two hours ; Cabinet 

 varnish is good, but rather longer in drying. Spirit varnishes are 

 worthless for this purpose, as they are brittle. About an equal 

 bulk of varnish should be added to the colour ; if less is used the 

 work will look dull, if more is used the colour will be wanting in 

 body. 



Before proceeding to lay on the coloured ring, it is a safe plan 

 to put on two or three coats of something which will prevent 

 running in. I have used two coats of Copal varnish, each to be 

 well dried before laying on another. I have also used a varnish 

 made of shellac dissolved in methylated spirit, and, as this is brittle, 

 I add about one-eighth gutta percha. This is a useful cement for 

 gelatine and glycerine mounts. The rings should have one or two 

 coats of pure varnish as a finish. Thos. Lisle. 



Saws of Saw-flies. — Saw-flies are of the order of Hymenoptera ; 

 they are separated from the Bees and Wasps by the fact of having 

 the abdomen united to the thorax by its whole breadth, instead of 

 being merely connected to it by a short tube or a foot-stalk. 

 Their mouths are not unlike the mouths of wasps,, but their'con- 

 struction is simpler, the labium (lower lip) not being so highly 

 developed, although considerably more complicated than the labia 

 of beetles. The lamily of the Te/it/ircdiiiidie are true saw-flies ; 

 but I believe that the corn saw-fly, Cc'p/inspygmce7is, is a connecting 

 genus between the Tcnthredinidce and the Siricidcv, whose oviposi- 

 tors are more like the ovipositors of the Ichneiimonidoi. The 

 mouths of Siricidiz are very small ; the mouth of Sirex gigas, or 

 Giant saw-fly, which is the largest of the Hymenoptera, and 

 bigger than a hornet, is much smaller than the mouth of the com- 

 mon wasp. Indeed, its parts are so rudimentary, that I doubt if 

 the insect ever eats, or if it does it can eat but little. I have, 

 however, no direct evidence on this point. I believe the saws of 

 the genus Lyda are adapted for cutting very soft leaves, for the 

 teeth are very large, and their form, which is not only that of teeth 

 along the edge, but of projecting ribs from the blade of the saw, 

 seems admirably adapted to prevent them from clogging. It was 

 stated in Science Gossip, some years back, that the egg does 

 not, as was formerly supposed, come down between the blades of 

 the saws, but that it is laid by a proper ovipositor, which is like the 

 ovipositors of the 1 )iptera. I regret that I have never dissected 

 a saw-fly with sufficient care to prove this statement, but I have 

 little doubt of its truth. H. M. J. Underhill. 



