NO. 6 PREPARATION OF COLEOPTERA VALENTINE I3 



VII. LABELING 



There exists an established precedent of long standing that pin 

 labels, when oriented parallel to the specimen, should face to the 

 right. This custom originated at a time when hand-lens observa- 

 tions were the rule ; its function was to insure legibility of labels 

 when specimens were examined in the left hand, the right remain- 

 ing free for manipulation of the lens. Since the binocular dissecting 

 microscope has come into almost universal usage in entomology and 

 the lifting of specimens with the right hand is, ordinarily, the safer 

 procedure, it follows that a system which would permit labels on 

 specimens held in the right hand to be read without rotating them 

 is to be preferred. Consequently, the writer recommends pinning 

 labels for slip mounts through the right end so that the printing will 

 face left. Additional reasons for this procedure are these : There is 

 usually a pinning space in the uneven right-hand margin of a label ; 

 and also, any identification label thus oriented may, when desired, be 

 swung into the standard, left-hand position without becoming in- 

 verted. Labels on specimens pinned individually, without mounting 

 support, had best be pierced through the center and oriented facing 

 left, parallel to the specimen. 



Double-ply Reynolds bristol board or single-ply Strathmore makes 

 an admirable label paper of the proper thickness to grip the pin effec- 

 tively. Should a label work loose, a drop of acetate cement on the 

 under surface around the pin will serve to fasten it securely. 



VIII. MOUNTING DISSECTIONS 



Preparations of mouth parts, legs, genitalia, etc., may be attached 

 dry to the mount bearing the specimens which yielded them. Should 

 a transparent preparation be required, the subject, partly dried on 

 absorbent paper, can be both cleared and dehydrated in xylol, and 

 from this transferred directly to a drop of balsam on the glass or 

 acetate mounting slip close to the specimen to which it belongs. After 

 proper orientation of the dissection by means of a needle, a tiny 

 square of cover glass, or thin acetate sheeting (7.5 gauge), is placed 

 over it. Another method, useful in attaching cleared preparations to 

 specimens mounted individually, is to prepare a small balsam mount 

 on one end of a rectangle of acetate sheeting and run the pin through 

 the opposite end. When not being examined, such a mount may be 

 swung out of the way under the specimen. 

 __ Bulkier genitalia, which require examination in more than one 

 H plane, may be conveniently prepared for study as cleared objects 



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