184 MR. C. B. HARDENBURG 



ical preparations, the glycerine present makes thorough 

 dehydration a very difficult mtatter. Pure alcohol of be- 

 tween 70% and 80% we haye found the best. Before put- 

 ting the specimen into the alcohol the larya should be 

 killed by dropping it into boiling water and should be 

 left there for a few minutes. Death is practically in- 

 stantaneous, and the larya at first contracts, but after a 

 few minutes stretches to its fullest extent. This allows 

 all structures on the segments to be easily examined. 

 Also, the boiling sterilises the contents of the larva. If 

 this is not done, it often happens, especially in the larger 

 specimens, that the alcohol will not penetrate quickly 

 enough througiiout the larya to prevent decay of the inner 

 parts. The result is that, in many cases, we have, after 

 a short time, a half decayed, flaccid larya, suspended in 

 a murky fluid, and hardly fit for future examination. 



The first alcohol should be renewed after about ten 

 days. 



Preparing Larvae for the Cabinet. 



Although much has been written on this subject and 

 many methods have been proposed, the ideal procedure, 

 which would show the caterpillar as it appears in nature, 

 has, to our knowledge, not yet been found. The method 

 which, with all its adherent disadvantages, has proved 

 of the most satisfactory thus far is that of emptying the 

 larva of its contents and inflating the skin over a small 

 oven until dry. The procedure which I have seen fol- 

 low^ed in the majority of cases is this : The larva is killed 

 either by cyanide, choloform or ether, a pin inserted into 

 the anal opening and by turning this around, the con- 

 nection between the rectum and the skin is severed. Then 

 the larva is pressed by rolling a ])eiH'il or a glass tube 

 over it, starting behind the head and working towards 

 the posterior end, and thus the contents of the caterpil- 

 lar are removed. Then a straw or a glass tube is in- 

 serted into the anal aperture, the hind part of the larva 

 tied or glued to it, or held to it by means of a small 

 clamp, and the skin inflated over a small oven until dry. 



