THE society's NOTE-BOOKS. 249 



as is well known, are furnished with viscid hairs to enable them to 

 walk on vertical or smooth surfaces. It would be rash, however, 

 to assume that their use is the same in other insects. What a 

 curious appearance the cancellated structure of the thorax of this 

 insect presents ! 



A. Hammond. 



Glow-Worm.— With regard to the legs of the male Glow-Worm, 

 is it not the penultimate joint of the tarsus which is bilobed, this 

 being one of the characteristics of Lampyris nodilicca ? Many 

 other beetles have the same double-joint. 



C. F. George. 



Saws of Saw-Fly.— I append sketches (PI. 42, Figs, i, 2, 3) 

 from two specimens in my own collection. By comparing Fig. i 

 with Fig. 3, the way in which the saws perhaps work up and down 

 the back pieces may be understood. I say " perhaps " because I 

 fancy that the two parts of the saw are kept fitted together, as in 

 Fig. 3. However, at any rate, the back of the actual saw is 

 grooved, and in the groove the back piece can be moved, as will 

 be seen in Fig. 2, which is the tip of Fig. i more highly magni- 

 fied. These back pieces, in many respects, are toothed as in Figs. 

 I and 2, while in some they are only minutely serrated, as in Fig. 

 3. The elaborate construction of the teeth of the saw is wonder- 

 ful, and the careful comparison of many species is a most interest- 

 ing study. Fig. 2 shows that each tooth is serrated, and some- 

 what strengthened by the chitine of the blade being thickened in 

 transverse lines. In Fig. 3 the teeth are not serrated, but the 

 strengthening is more curious. Each tooth is^ as it were, on a rod 

 or bar of chitine. These rods spring from a thickening of the 

 chitine, which runs all down the blade, and this again is supported 

 by other bars springing from the strong rib of the saw, which 

 reminds one strongly of the piece of brass affixed to a carpenter's 

 tenon saw. The rib can be plainly seen in Fig. 2. 



It used to be said that the fly laid the egg by passing it 

 between the two saws. This account was shown to be incorrect 

 by a paper in " Science Gossip " a few years ago. It is easy to 

 find the real ovipositor as there drawn. 



H. M. J. Underhill. 



Saw-Fly.— To illustrate the structure of the Feet of Saw-Fly, I 

 add a drawing of the foot of a species of Allantus (PI. 42, Fig. 4). 



