2M> THE ENTOMOLOGIST. 



blotting-paper or soft rag in a straight position, and roll it 

 firmly with a piece of glass tube, from head to tail, till all the 

 contents are evacuated. It is best to begin rolling about the 

 middle of the larva, for if the contents are driven too suddenly 

 towards the extremity there is danger of bursting the skin: 

 it is also to prevent this that the fine needle is first intro- 

 duced. Traction with forceps on the extended viscera aids 

 the ))roce.ss. When empty, the skin, which is now shapeless 

 and shrivelled, must be taken in the left hand, and the 

 aperture at the extremity opened fully with the forceps ; the 

 nose of the spring-tube is now introduced for a short distance, 

 sufficient to allow the piece of watch-spring just to catch the 

 tip of the anal Hap ; on blowing gently into the tube the skin 

 will rise into shape, but will collapse instantly on ceasing the 

 inflation. If the tube be very small, or the aperture in the 

 animal large, the disproportion will allow of such an escape 

 of air by the side of the tube that either the skin will not 

 properly inflate or only do so by blowing fiercely. The 

 happy mean in this, as in all things, can only be hit off by 

 experience. The last segment may be pressed to the tube, 

 and so made to fit closely enough. Indeed, it is no advantage 

 to have an exact fit ; some escape is desirable, so as to act 

 as a safety-valve, and prevent the over distension of the 

 specimen ; occasionally it is well to prick the thin skin 

 connecting the 2nd segment with the head, to prevent the 

 latter being unnaturally forced forward. All being so far 

 prepared, slip one end of the india-rubber tube over the free 

 extremity of the spring-tube, and the other over the delivery 

 tube of the pressure-bottle ; now press the ball, and the skin 

 will expand ; and if the right balance between the size of the 

 spring-tube and the aperture in the larva has been hit off, the 

 skin will remain inflated with occasionally squeezing the 

 ball. Light the spirit-lamp and put it in its place (higher 

 than in the woodcut), so that the flame shall enter the 

 opening in the box ; lay the skin, attached of course to the 

 spring-lube, on a flat piece of cork — the "tray," and fasten it 

 by an elastic band, as shown in figure 3 ; now put the cork 

 into the oven, so that the larva lies well inside, and with a 

 wooden American clip (clothes-peg) secure the side of the 

 cork to the slab of tin that projects from the opening; 

 continue the inflation, watching the degree to which the skin 



