74 KANSAS UNIVERSITY QUARTERLY. 



uniformly specialized, that it is often only through such exhibitions 

 of retrogression as the above that the line of specialization of the 

 scales can be determined. 



In Hcniaris tlixsbc and among the Sesiidae the clear areas are quite 

 destitute of covering. It seems evident that this disappearance of 

 scales is one of the adaptive changes accomplished during the long 

 process of selection which has resulted in giving the Sesians their 

 familiar and striking superficial resemblance to wasps and bees, a 

 protective resemblance of evident value. Among the Attacids, the 

 clear spots on the wings of Promctlwa and Lima are without scale- 

 hairs; in Sai/iia c-yiif/iia t\\e. clear spaces are covered with scale-hairs 

 which rather plainly gradate into the scales of the scaled areas. In 

 CosiiiosoiNii and DiJasys, clear-winged Zyga'nids, the clear areas are 

 sparsely covered with scale-hairs which more or less clearly show a 

 gradation into the specialized scales of the scaled areas. The absence 

 of scales from the major portion of the wings of these clear-winged 

 forms shows that by a thickening of the wing-membrane or by adapted 

 venation, a substitute for the scale-strengthening has been developed; 

 or that the advantage of protective resemblance gained by the 

 disappearance of the scales is greater than the advantage gained by 

 the presence of the scales to strengthen the wing-membrane. 



The scales of Coleoptera, however they may have arisen, serve 

 solely now, probably, for producing color and marking. Occuring, 

 as they do, chiefly on the horny elytra they apparently have no 

 present strengthening or protecting function. Scales are present in 

 many groups of beetles, being especially often met with among the 

 Curculionidse. Fischer* found scales among the Cleridse, Ptinidre, 

 Dermestidae, Byrrhidte, Scaraba^idK and Curculionidte. Dimmock* 

 adds to these families containing scale-bearing forms the Elateridie, 

 Cerambycidie, and "with some doubt, the Buprestidce." 



In a Brazilian Curculionid examined by me the body of the beetle 

 was bronze-golden and white with occasional small, shining, black 

 tubercles on the elytra and pronotum. These black tubercles were 

 without scales, but the golden and white colors were caused by small 

 elongate scales. These scales were not arranged on the body in 

 regular rows, but were sufhciently numerous to overlap considerably. 

 The white scales were flattened elongate with nearly parallel sides, 

 entire outer margin, and bore striae about .006 mm. apart. The 

 golden scales were about. 286 mm. in length, .043 mm. wide near 

 insertion of pedicel and .028 mm. vvide at outer end, and bore stria3 



*Fisclier. Tj. H.. Microscopische Untersucliungeii uber die Kaeferschuppen. Disserta- 

 tion, Fi-eiburg, 1846. 



tDimTnock. Geo. The scales of Coleoptsra, Psyche, vol 4, pp. 3-11, 23-27, 43-47, 03-71. 1883, 

 Cambridge. Mass, 



