DIFFERENCE OF TEXTURE 105 



just under the other, so that when the mandibles are tightly- 

 closed, scarcely any space is left between them. 



The colour of this Beetle is simply black, but it has a sort of 

 satiny appearance which can only be explained by the magnify- 

 ing glass. To the unaided eye both the elytra and the rest of 

 the body have the satiny gloss, but with a difference of texture, 

 like that of two qualities of satin. How this difference is ob- 

 tained the lens reveals. The head and thorax are covered with 

 myriads of raised semi-globular prominences, very similar in shape 

 to those which stud the petal of a flower — say a geranium, and 

 give it the peculiar softness which no pencil can even approach. 



If we double a petal of a geranium, and place the folded 

 portion under the microscope so as to look along it, we shall 

 find that the edge, instead of being quite straight, is studded 

 with a row of little semi-conical projections, thus -~~ '-~>~-^ . 

 each being in fact a partially developed hair. Now, if we take a 

 portion of the present insect, or of any insect which possesses 

 a similar texture of surface, and manage to get a side view of it, 

 we shall find that it is studded with almost similar projections, 

 they being partially developed spines or spikes. If, however, 

 we shift our lens to the elytra, we shall see the difference of 

 texture at once explained ; for the surface, instead of being 

 studded with little projections or "pustules," is covered with 

 little hollows or punctures, each much the same size as the 

 pustules. 



There are many foreign Dorcidoe, one of which, Dorcus Antceus, 

 has already been mentioned. The only other species that pre- 

 sents any distinctive points is Dorcus Dehaanii. The elytra of 

 the female are covered with parallel rows of shining black ridges, 

 and between each of the ridges is a double row of very large 

 and deep punctures. These punctures are as dull as the ridges 

 are bright, so that there is a very bold contrast between them. 



There is a small British Beetle, familiar to entomologists who 

 know where to look for it, but scarcely ever seen by others. 

 It is called Sinodcndron ci/lindricum, and it inhabits decaying 

 wood, being generally found within fallen ash-trees. Its cylin- 

 drical body points it out at once as a boring Beetle, as does that 

 of the Dorcus, and, indeed, these two insects are often found 

 inhabiting the same tree. 



