226 THE ENTOMOLOGIST. 



the air into the larva a glass tube, drawn out to a point, is 

 necessary ; several sizes should be prepared. This we will 

 call the "spring-tube." It is best made of German hard 

 glass, as it is less liable to accident, and will serve a long 

 time. The size of the tube is not always proportionate to the 

 size of the larva ; often a small larva requires a larger tube 

 and more inflation than a large one : thus, Vanessa polychloros 

 requires a larger tube than Dicranura vinula, and more 

 inflation. The best way to attach the larva to the tube is 

 undoubtedly that described by Mr. Auld in last year's April 

 number of the ' Entomologist,' where a figure of the tube is 

 given; only we recommend but one steel spring, two — one 

 above and one below — being, in most cases, not only 

 unnecessary, but mischievous, as the under spring is apt to 

 force the last pair of prolegs out of their place, and perhaps 

 to break them oflT. However, this can be left to the fancy of 

 the operator. The steel spring can be fastened to the tube 

 by simply binding the two together with thread and securing 

 with sealing-wax. 



The oven in which the larva is baked is made out of a 

 one-pound Colman's mustard-tin, prepared in the manner 

 shown in the woodcut (fig. 1). Draw a knife along the 

 soldered junction of one of the broad sides with the bottom, 

 and then up on both sides from the extremities of the first 

 incision towards the lid for rather less than two inches ; the 

 flap thus cut must be turned up into the cavity of tiie box to an 

 angle of 45*^, as the dotted line indicates. A second opening 

 must be made in one of the narrow sides, of the shape and in 

 the position shown : begin it two inches from the bottoui of 

 the box, close against the flap above mentioned ; it should 

 measure two and three-quarter inches across at its lower 

 part, and one and a half inch above ; its height should not 

 exceed one inch and a quarter. The piece of tin removed 

 from the hole, and still retaining its connexion with the box, 

 should be turned down into the horizontal position, so that 

 it may serve as a slab on which to rest the cork tray that 

 carries the larva, and which is pushed into the opening. It 

 is also a great convenience to have a piece of glass let into 

 the lid, so as to admit more light. VVhen in use the box is 

 to stand on the broad side that has the first-described hole 

 in it; it should be placed on a tripod or small retort-stand, 



