NO. 6 PREPARATION OF COLEOPTERA — VALENTINE II 



slip method entails some sacrifice of utility, safety, and uniformity. 

 On the other hand, an obvious advantage in pinning lies in the result- 

 ing mobility of individual specimens. Whichever method is chosen, 

 the quality of the finished product depends, to a large extent, upon 

 two factors: proper killing (I) and adequate degreasing (11). 



In mounting Coleoptera, the location of the pin is internationally 

 agreed upon : It should enter the anterior discal portion of the right 

 elytron and emerge on the right side between the mid and hind legs, 

 passing through the metasternum laterad of the mid line; it should 

 be so oriented that both longitudinal and transverse axes of the beetle 

 are at right angles to it. The writer recommends the European sys- 

 tem of appendage arrangement as combining neatness and compact- 

 ness with maximum visibility. The head and pronotum are extended, 

 with antennae close to the dorsal surface and directed straight back ; 

 the legs are directed downward and toward the pin, but with femora 

 more or less horizontal and close to the body, the anterior femora 

 pointing forward, the mid and hind pairs pointing backward. A 

 fresh specimen naturally assumes this attitude when pinched laterally 

 between the fingers. If the insect has been killed with ethyl acetate, 

 its appendages will usually dry in position without the necessity of 

 guard pins. However, drooping of the head and pronotum may oc- 

 cur. This can be remedied easily by resting the jaws (open if possi- 

 ble) of the drying specimen on an outwardly inclined pin placed 

 before it (fig. 2). 



VI. GAUGING 



jMounting specimens at an approximately uniform height not only 

 makes for neatness in the collection but facilitates microscopic com- 

 parisons. Two or three standard heights should be decided upon as 

 proper for corresponding categories of beetles of different body 

 depths, and a" gauge constructed which will automatically elevate the 

 mounting support to the desired distance on the pin. 



A glass-topped, slotted pinning block greatly facilitates both pin- 

 ning and gauging. It can easily be constructed of plaster in a mold 

 slightly larger (about -| inch on each side) than the future glass 

 working surface. The latter is composed of two pieces of plate glass, 

 each 3 inches square, aligned along one edge but held slightly apart 

 by two narrow strips cut from the ends of a microscope slide, in- 

 serted in the slot between the plates at the corners, and cemented 

 there in an upright position. The thickness of these lateral pieces 

 should gauge the width of the slot just to accommodate the shaft of 

 a No. 5 insect pin. Two microscope sHdes are then placed at right 



