BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [80] 



hours. Larger specimens require from two to three days. More rapid 

 relaxing may be caused by the use of steam, and a flat piece of cork with 

 the specimens laid or x)inned thereon and floated on the top of hot water 

 in a closed vessel constitutes an excellent relaxing arrangement. 



Inflation of the Larvce of Lepidoptera. — The larvae of Lepidoptera pre- 

 served in alcohol are excellent for anatomical and general study, but 

 are not very suitable for use in economic displays. This means of 

 preservation also has the disadvantage of not generally preserving 

 the natural color and appearance of the specimens. These objections 

 may be avoided, however, by the dry method of preserving larvae, viz, 

 1by blowing or inflation. The process may be described as follows: 

 The larva may be operated upou alive, but should preferably be first 

 killed by dipping in chloroform or alcohol, or in the cyanide bottle. It 

 is then placed on a piece of blotting paper and the alimentary canal 

 caused to protrude from one- eighth to one-fourth of an inch, by rolling 

 a pencil over the larva from the head to the posterior extremity. The 

 protruding tip is then severed with a sharp knife or pair of dissecting 

 scissors, and the contents of the abdomen are forced out by i^assing a 

 pencil, as before, a number of times over the larva. Great care should 

 be exercised in expressing the fluids not to press the pencil too strongly 

 against the larva or to continue tlie operation too long, as this will, 

 especially in delicate larvse, remove the pigment from the skin, and the 

 specimen when dried will show discolored spots and be more or less 

 distorted. The larva should be moved from place to place on the blot- 

 ting paper during the operation, so as not to become soiled by its own 

 juices. A straw, or a glass tube drawn to a point at the tip, is then 

 inserted in the protruding portion of the ahmentary canal. If a straw 

 is used the larva may be fastened to it by thrusting a pin through the 

 wall of the canal and the straw. In the case of the glass tube the ali- 

 mentary c anal can be caused to adhere by drying for a few minutes 

 and this operation may be hastened and the fastening made more 

 secure by touching the point of union with a drop of ghie. The straw 

 or glass tube is then attached to a small rubber bag, previously inflated 

 with air, the ordinary dentist's or chemist's gas bag answering admir- 

 ably for this purpose. The larva is now ready for drying, and for this 

 purpose a drying oven is required into which it is thrust and ma- 

 nipulated by turning it from side to side, to keep it in proper shape and 

 dry it uniformly until the moisture has been tlioroughly expelled. An 

 apparatus which I have found very convenient for this purpose is rep- 

 resented at Fig. 109. It consists of a tin box with mica or glass 

 slides, e, to allow the larva to be constantly in sight. It has also a 

 hinged to p, &, which may be kei^t closed or partly open, or entirely 

 open, as may be necessary, during the operation. The ends of the 

 box are prolonged downward about 5 inches, forming supports for 

 it, g. Beneath it is placed an alcohol lamp, f which furnishes the 

 heat. In the end of the box is a circular opening, d, for the introduc- 



