NO. 6 PREPARATION OF COLEOPTERA VALENTINE 3 



the day's catch to remain in the killing bottle at least overnight, in 

 order to insure the maximum relaxing effect of the vapor-filled atmos- 

 phere. Insects may thus be preserved, while awaiting mounting, for 

 an indefinite period, especially if they receive an occasional wetting of 

 ethyl acetate. It is better, however, to remove them for drying, de- 

 greasing (II), or preserving in fluid (X) before many weeks have 

 passed. 



Advantages : 



1. Specimens killed by the fumes of ethyl acetate are completely 

 relaxed and retain their flexibility when subsequently degreased in 

 ether (II) or preserved in Barber's fluid (X). Success in mounting 

 such material on a flat, smooth surface, or in arranging appendages 

 after direct pinning, or in relaxing specimens that have dried is far 

 greater than when either cyanide or alcohol has been used as the 

 killing agent. 



2. Unlike the average cyanide jar, an ethyl acetate-charged killing 

 bottle acts promptly, permanently, and uniformly over a considerable 

 period of time. Insects show no tendency to revive if they are allowed 

 to remain in the lethal atmosphere a few minutes after all motion has 

 ceased, and delicate Lepidoptera as well as powerfully jawed beetles 

 usually succumb before they can injure themselves or other specimens 

 in the same bottle. 



3. No fading or discoloration has so far been observed by the 

 author as a result of killing beetles and their larvae with ethyl acetate. 

 However, the green pigment of certain moths may turn yellow if the 

 specimens are not removed from the killing bottle as soon as dead. 



4. The use of ethyl acetate presents no such hazard as does cyanide, 

 which is far more toxic to human beings. 



5. Ethyl acetate is an ingredient of the relaxing fluid described 

 below (XI) and a solvent for cellulose cement ; hence its use as a kill- 

 ing agent simplifies the field technique by reducing the number of 

 necessary fluids to be carried on a trip of long duration. 



II. DECREASING 



The use of some lipoid solvent in the preparation of Coleoptera, 

 especially carabid, cicindelid, and scarabaeid material, is of the great- 

 est importance. Ordinary sulfuric ether ^ (the commercial product) 

 suffices very well. Specimens should be soaked in ether until the 



1 Ether can be conveniently and economically stored in i -pound cans fitted 

 with small screw caps seated with cork. While in use as a grease solvent, it 

 will keep well in tightly corked homeopathic vials. 



