54 BULLETIN 6*7, UNITED STATES NATIONAL MUSEUM. 



almost all requirements except for minute insects. In length these 

 pins vary from 34 mm. to 40 mm. The latter length is rarely recom- 

 mended. Most collectors prefer a 34 mm. or 35 mm. (If inches) for 

 all insects except Lepidoptera, Orthoptera, and Neuroptera, for 

 which 37 mm. or 38 mm. (1^ inches) is recommended. Some Diptera 

 (Asilidse) and Hymenoptera (Ichneumonidse) should have a 37 mm. 

 pin. 



It would be very advantageous if collectors generally would agree 

 on certain lengths, as* it would make our collections more uniform, 

 especially where there is much exchanging of specimens. 



These pins are mostly made in Germany, and are known as Klaeger, 

 Karlsbader, Schleuter, etc., but several of the American dealers now 

 make a pin of their own very similar to the foreign pins, and some 

 claim of better quality. The black or japanned pins should be used 

 for pinning most insects, while the bright or white pins may be used 

 for points and all double mounts. The bright pins are apt to verdi- 

 gris — that is, produce a green substance near the insect which will 

 eventually rot the pin as well as mar the appearance of the insect. 



Fig. 96.— A pinning block. 



There are, however, a few groups of insects that do not verdigris, and 

 for these bright pins are as good as black. Many aquatic insects and 

 those whose larvae feed in wood are more apt to verdigris than other 

 forms. 



The English use shorter pins, but these are not in use now in the 

 United States. Nickel pins are also obtainable from dealers. For 

 small insects many entomologists use very short and slender pins, 

 about 14 mm. long, without heads, known as "minutien nadeln," or 

 "micro-pins." Sometimes fine silver wire is used for this purpose. 

 It is handy to keep the pins in a pin tray or box. 



Insects should be pinned as soon as possible after they are dead; 

 the evening after collecting or the next day. Even specimens col- 

 lected in alcohol should be attended to without unnecessary delay. 

 Many fragile insects should be pinned in the field in a box taken along 

 for that purpose. It looks better to have the insects all at the same 

 height on the pins. For this purpose a pinning block is very useful. 

 One can be made by examining the figure (fig. 96), three blocks with 



