KANSAS UNIVERSITY' QUARTERLY. 



Fiff. 8. 

 Scale of Lyco- 

 uiorpha ooii- 

 Htans, showing 

 cross strias. 



striation. This condition obtains in the scale of Jfcplalits 

 (see fig. 7). Burraeister {Joe. cit.) has observed this differ- 

 ence of striffi in a Pyralid, Nomophila. 



In addition to the longitudinal strice some scales have 

 cross- striiTi, but as far as I have observed these cross-striae 

 do not intersect the longitudinal lines, but merely extend 

 transversely between them. Scales from Callidi-yas eiibiile 

 plainly show these transverse striae, which average 

 about .0009 mm. apart. In scales of Lycoinoyplia constans 

 (see fig. 8) similar cross-striae are about the same distance 

 apart as the longitudinal striae, namely .0014 mm. 



The scales are not evenly flattened, but the middle 



— ^^.^,<:;;;;;Sv;?;;;:^^^ portion of the scale- 



,^^7:=^=='^^^^''^'"^^ blade (see fig. 9) is 



Pj^^ J, thicker than the lateral 



Cross -section of scales of Piirnassius sinin- portions. The SCale is 

 theiis. (The stria; are 011 the surface not 



facing the wing-meiubraue.) also irregularly corru- 



gated, as shown in figure 9. In accounts of the structure of the scales by 

 various writers some errors of observation are apparent. Deschamps'^ 

 says that the scales are often composed of three superposed mem- 

 branes or lamellae. " Toutes les ecailles qui recouvrent les ailes des 

 lepidopteres me paraissent formees de deux et le plus souvent de trois 

 membranes ou lamelles. Sur la membrane sup6rieure se trouvent 

 les granulations dont se compose la matiere color^e de I'ecaille. 

 * * * Lorsque se presentent des strips, c'est toujours sur la deuxi^me 

 lamelle qu'elles sont posees." Deschamps was limited to studying 

 broken scales in which at best the making out of the structure, in 

 later days easily determinable by sectioning, would be a difficult 

 matter. 



A deal of rather unprofitable discussion among microscopists 

 regarding certain "beads" or "villi" alleged to be visible on the 

 scales of butterflies has been carried on. A paper by S. S. Mclntiref on 

 the external histology of scales sums up the writer's belief regarding 

 these "beads" as follows: " That the beaded appearances seen in 

 scales are due to the following causes, either singly or collectively: 

 (a), corrugations, taking the form of hemispherical embossings; (b), 

 pigments; (c), shadows of projections or folds in the membrane 

 either within or beyond the focus of the object-glass." 



Probably the best general account of scale-structure is that of 



*Deschamps, Bernard, Recherches microscopiques sur I'orgauization des ailes des 

 Lepidopteres. Ann. d. Sci. Nate, 'iva.%. serie, III, 1835, Paris. 



tMcIntire, S. S.. Notes on the minute structure of certain insects. Monthly Mic 

 Journal, vol. 5, 1871, Loudon, 



