4 Transadiom of the ["rSi.^'irS"' 



spoken of. Hence, if the tops of the coi-rugations only are in focus, 

 tliey appear as bright circular beads at pretty regular distances 

 upon a number of indistinctly defined bright lines running down 

 the scale longitudinally, but which sometimes anastomose with eacli 

 other. A httle deeper focussing dissolves this view, in which I 

 think " the spherule theory " takes its origin, and converts the 

 bright dots into " note of exclamation " markings nearly consecutive 

 with each other. The scale then appears to be scored with ridges, 

 like the exterior of one of the valves of a cockle-shell, but never- 

 theless it bears considerable likeness to the test scale — the scale of 

 Lejpidocyrtus Curvicollis. (See Fig. 5.) 



In the scale of Lepidoeyrius I recognize the same plan of 

 structure, and would account for the peculiarities of its appearance 

 by the more frequent anastomosing of the corrugations and the 

 greater minuteness of the costae, which structure renders it more 

 difiicult to trace the course of the ribs. Microscopists generally 

 also I think, fascinated by the beauty of the exclamation mark- 

 ings, have devoted all their efforts to the development of this 

 appearance, and have neglected to a great extent to read the struc- 

 ture of this object as interpreted by transmitted light at a very 

 oblique angle with the stage, and other modes of illumination at 

 their command, because these modes alter the view to one much 

 less captivating. 



I will say no more respecting this scale, since I can add nothing 

 to the accuracy or clearness of Mr. Beck's observations on the 

 subject* beyond expressing my belief that the '^ heads" are only 

 the most elevated points on the surface of the scale, which can be 

 focussed alone, the slightest alteration of the focus dissolving them 

 into the note of exclamation markings. 



In the scale of the Speckled Podura, Degeeria domestica of 

 Nicolet, a scale which I prize very highly iox its beauty, I seem to 

 find support in the opinion of the structure of the scale of Lepido- 

 cyrtus that I have formed. The insect is rare in England, but I 

 have reason to think its scales are often sold on the Continent, where 

 it is probably more abundant. The scale claims strong affinities 

 with the other Podura scales that I have mentioned in the single 

 characteristics it presents to the view ; but in uniting these features 

 in itself it is unique. For instance, it has minute cross-striae like 

 Macrotoma, the costae are interrupted, and tend to overlaj) each 

 other as in the Greenhouse Degeeria, while by direct transmitted 

 light it exhibits the " note of exclamation " markings of Templetoma 

 and Lepidocyrtus very beautifully ; but in uniting all these features 

 in itself it presents a perfectly distinctive character.f 



* ' Quarterly Journal of Microscopical Science.' 



t Occasionally, too, on certain scales the rid^^es anastomose very distinctly, and 

 at these points certain illumination will give an appearance not very remote liom 

 the so-called spherules or beads of Lcpidocijrtus. 



