NO. 6 PREPARATION OF COLEOPTERA VALENTINE 5 



Advantages : 



1. Ether effects the extraction of body fluids as well as complete 

 degreasing. After the ether bath, piceous, castaneous, and fulvous 

 specimens will acquire a remarkable freshness of color, lightly pig- 

 mented areas appearing in vivid contrast to dark as soon as evapora- 

 tion has taken place. Likewise, the true texture of the chitin, a 

 useful habitus character dependent upon clean microsculpture, will 

 be preserved as in life. 



2. Never soiled with a sticky layer of grease to which dust and 

 fine litter adhere, the ether-treated specimen can always be cleaned 

 with a dry camel's-hair brush with minimum danger to setae. 



3. The greaseless insect can be firmly cemented to the mounting 

 support ; should it become dislodged, its lightness and flexibility will 

 insure a good chance of survival intact. Specimens exuding grease 

 after they have been mounted on points or cards invariably discolor 

 the paper and not infrequently work loose ; when pinned directly, 

 they usually corrode their pins. 



4. Ether-treated specimens ac([uire atmospheric moisture rapidly 

 and never become brittle under ordinary climatic conditions. In this 

 respect they contrast very favorably with grease-soaked specimens 

 whose ligaments and musculature eventually harden. 



5. Swelling is accomplished by means of the ether bath, specimens 

 killed with the fumes of carbon tetrachloride becoming so turgid in 

 ether that usually the aedeagus and frequently its internal sac are 

 extruded (III). This may be a great advantage, insofar at least as 

 small carabids are concerned, since it eliminates the difiicult process 

 of dissecting such material. The more moderate distention of ethyl 

 acetate-killed specimens in ether is useful not only in the extraction 

 of genitalia, but also in the preparation of soft-bodied larvae (IX). 

 Soaking in ether, however, will not cause swelling or extrusion of 

 genitalia in previously dried material. 



There are, of course, other satisfactory, though perhaps not equally 

 efficient, lipoid solvents which may be used in place of ether. Chloro- 

 form, benzol (benzene), and diethyl carbonate all yield good results 

 l)ut tend neither to be imbibed nor to expel body fluids so readily. 

 Xylol (xylene) is pleasant and convenient to use, but its tendency to 

 stiffen articulations and to deposit a whitish film are disadvantages. 

 Chloroform is the only one of these solvents heavy enough to float 

 both the specimens and their extracted body fluids, a fact which 

 makes it desirable to separate the two with a wire screen. Ether, 

 on the other hand, being lightest of all, permits both to sink, while 

 diethyl carbonate, xylol, and benzol effect a more or less temporary 



