560 



INSECTS AND ARACHNID A. 



FIG. 28-2. 



the former of these modes ; and nothing is easier than to 

 mount portions of the elytra of the former (which are usually the 

 most showy portions of their bodies), or of the 

 wings of the latter, in the manner described 

 in 123. The tribe of Curculiomdcc, in which 

 the surface of the body is beset with scales 

 having the most varied and lustrous hues; is 

 distinguished among all other Coleoptera for 

 the brilliancy of the objects it affords ; the 

 most remarkable in this respect being the 

 well-known Curculio imperialis, or "diamond 

 beetle" of South America, parts of whose 

 elytra, when properly illuminated and looked 

 at with a low power, show like clusters of 

 jewels flashing against a dark velvet ground. 

 In many of the British Curculionidee, which 

 are smaller and far less brilliant, the scales lie 

 at the bottom of little depressions of the sur- 

 face; and if the elytra of the "diamond beetle" 

 be carefully examined, it will be found that 

 each of the clusters of scales which are arranged 

 upon it in rows, seems to rise out of a deep 

 pit which sinks in by its side. The transition 

 from scales to hairs is extremely well seen, by 

 comparing the different parts of the surface 

 of the "diamond beetle" with each other. 

 The beauty and brilliancy of many objects of this kind are in- 

 creased by mounting them in cells in Canada balsam, even 

 though they are to be viewed with reflected light ; other objects, 

 however, are rendered less attractive by this treatment ; and in 

 order to ascertain whether it is likely to improve or to deterio- 

 rate the specimen, it is a good plan first to test some other por- 

 tion of the body, having scales of the same kind, by touching it 

 with turpentine, and then to mount the part selected as an ob- 

 ject, either in balsam, or dry, according as the turpentine in- 

 creases or diminishes the brilliancy of the scales on the spot to 

 which it was applied. Portions of the wings of Lepidoptera are 

 best mounted as opaque objects, without any other preparation 

 than gumming them flat down to the card-board surface of the 

 slide ( 123) ; care being taken to avoid disturbing the arrange- 

 ment of the scales, and to keep the objects, when mounted, as 

 secluded as possible from dust. In selecting such portions, it is 

 well to choose those which have the brightest and the most con- 

 trasted colors, foreign butterflies being in this respect usually 

 preferable to British ; and before attaching them to their slides, 

 care should be taken to ascertain in what position, with the 

 arrangement of light ordinarily used, they are seen to the best 

 advantage, and to fix them there accordingly. Whenever por- 

 tions of the integument of Insects are to be viewed as transparent 



A, Hair of Myriapod. 



B, Hair of Dermestes. 



