PRESERVATION OF LAkV^ BY INFLAIION, 



227 



Fig. 1. 



or if these are not to be had it can be balanced on a brick 

 standing on end. It is essential that the ))art of the box in 

 which is the first hole should pro- 

 ject free of the support, so that 

 the Hame of the spirit-lanip (or 

 gas jet) that gives the heat may 

 enter the aperture. If gas be em- 

 ployed a Bunsen's burner, turned j 

 low, should be used. It will be 

 understood that a larva put head 

 first into the pyramidal, or second 

 hole, will be exposed along its 

 whole length at once to the heat 

 of the flame that is burning in at 

 the first hole, while the flap of tin 

 that was turned upwards into the 

 box not only prevents scorching, 

 but equally distributes the heat all 

 along the breadth of the oven. 

 The sizes given for the apertures 

 are found the best for this sized 

 oven, and had best be carefully followed. To suspend the 

 larva by its tail in a vertical position, with the flame just 

 beneath it, as shown in the figure accompanying Mr. Auld's 

 paper, before referred to, is, we believe, a miscalculated 

 procedure, for surely the "head and shoulders" would be 

 singed before the tail was half dry ; also in the summer 

 weather, when larvae are easy to obtain, it could hardly be 

 agreeable to spend an afternoon standing with one's face 

 bending over the flame of a spirit-lamp. 



We will now describe the pressure-bottle, by means of 

 which the air is ibrced into the larva. Obtain a strong 

 bottle of not less than twenty ounces (one pint) capacity, 

 about an inch and a half across the mouth : these can be 

 bought at any chemist's; certain drugs are sent out in them 

 from the wholesale houses. Get an india-rubber cork, 

 exactly fitting and bored with two holes; into one of these 

 holes a piece of glass-tubing three inches long is inserted 

 (this is the "delivery tube"), and into the other a similar 

 piece of glass tube, only double the length, so that it may 

 project freely into the cavity of the bottle, and rise free of 



