PSYCHE. 



THE SCALES OF COLEOPTERA. 



GEORGE DIMMOCK. CAMBRinGE, MASS. 



(^Cotifiifitcd fill III pa(^e ^7.) 



The brown srak-s are lustreless ami 

 withiiut cross-bands, while the white 

 scales, as long as they are filled with 

 air. are silvery. I'his I'act antl other 

 reasons lead me to believe that the cross- 

 Ijands are partial separations of the 

 lower lamina of the scale, and are the 

 cause of the silvery lustre of the white 

 scales. I reserve, however, further dis- 

 cussion of the procluction of silver\" sur- 

 faces for the last portion of this paper. 



To get at the finer structure of these 

 scales transverse sections of some of the 

 brown ones were made ; one of these 

 sections is shown in f;g. 7. d . Altho 

 numerous sections as thin as 0.0035 •'''"n- 

 were examined, I could find no longi- 

 tudinal canals or passages, but the lower 

 lamina of the scale is somewhat more 

 transparent than the upper lamina ; on 

 the latter portion are the longitudinal 

 striae, seen in transverse section in fig. 

 7. d. Sections of the white scales are 

 similar in form, but are so transparent 

 in the fluids in which I was obliged to 

 study them that I could find no air 

 cavities. 



Treatment with reagents give positive 

 proof tiiat both the white and brown 

 scales contain air. Alcohol or water 

 rapiilh' discharges air from cavities 

 within them ; glvcerin expels it onlv less 



rapidh . Scales regain their air readily 

 when dried from water or alcohol. Af- 

 ter treatment with any liquid the white 

 scales become very transparent, showing 

 that they contain no coloring matter ; 

 when moimted in Canada balsam thev 

 are almost invisible. 



KI.MEUIDAE, SPECIES UNDETERMINED. 



Fig. 8 represents the scales from an 

 undetermined species of elateridae. 

 from Leipzig, Germany. I figure them 

 here because I have found in no other 

 coleoptera scales of similar form. They 



P<g. S. Scales of an undetermined species of elater- 

 idtie: a, seen from ahove ; f\ lateral view. Enlarged 100 

 diani. 



are. however, similar in structure to the 

 brown scales of A/a //s ocu/a/us. but thev 

 liave in addition a prolongation of the 

 distal end of the scale into a sort of short 

 filament. 



SCALES OF PTINIIS .■'RUTIEUS. 



A species of Ptinus, probably P. rii- 

 ///z/.?, wdiich was found in great numbers 



