THE PRESERVATION OF SPECIMENS. 



297 



FIG. 261. 



they may serve very well the purposes of a tempora- 

 ry study. 



THE PINNING OF SPECIMENS. The appearance of 

 a collection of insects depends greatly upon the care 

 taken in pinning the specimens. Nearly all insects 



should be pinned 



through the mid- 

 dle of the thorax. 



Many bugs (He- 



miptera) are best 



pinned through the 



scutellum (Fig. 



261), and beetles 



are pinned through 



the right wing-cov- 

 er at about one fourth its length from the base (Fig. 

 262). About one fourth of the length of the pin 

 should be allowed to project above the specimen ; 

 uniformity in this respect will add greatly to the 

 neatness of the appearance of the collection. 



A convenient device for securing uniformity is 

 what may be termed a pinning block. This is made 

 from strips of wood which are 

 one fourth as thick as the pins 

 are long, and which are fas- 

 tened together as shown in 

 Fig. 263. A hole just large 

 enough to allow the passage 

 of the head of an insect pin is bored through the 

 center of each of the steps of the block. In pinning 

 an insect the pin is pushed through the insect so that 

 less than one fourth of its length projects above it, 

 and then the insect is pushed back into place by in- 



FlG. 263. A pinning block. 



