70 



PSYCHE. 



[July— August iSS.5. 



figured tlieiii in iiiv dissertation^'^ and in 

 Psyc/ie.*^ Q\ the transverse section of 

 a scale of Alans, figured in this paper, 

 it will be seen that there too the striae 

 are upon the outer surface. Tlial I 

 have foiuul to be the case with the 

 principal or external striae, in all beetle- 

 scales which I have examined. It is, 

 briefly expressed, only the development 

 of a mechanical law. which extends to 

 many surfaces which shrink by drying 

 or cooling. It can be easilv illustrated 

 bv partly filling a bladder with water 

 and allowing it to dry upon a board. 

 The main folds will be, of course, upon 

 the exposed upper side, and the longi- 

 tudinal ones will be the more prominent. 

 Another easv wav to pro\e that the 

 striae upon tiie scales of the wings of 

 iepidoptera are upon the side away from 

 the wing is to take impressions of tlie 

 scales upon a surface of collodion. 

 These impressions are readily taken by 

 pressing quite lightly a dry butterfl\-'s 

 wing upon a microscope slide whicli 

 has been moistened with a solution of 

 collodion in ether. The wing shouUl 

 be removed before the collodion has 

 become thoroughly dr\-, when beautiful 

 impressions of the outer surface of the 

 scales will remain on the collodion 

 surface, and may be mounted for future 

 study. A very little practice will 

 enable one to remove the wing at tlie 

 proper moment ; if left too long the 

 greater part of the scales will be re- 



■i^Dimmock, G. The anatomy of the mouth-parts 

 and of tlie suckinj^ apparatus of some diptcra. Disser- 

 tation . . . Leipzig university . - . iSSi. 1*1. i, fij>. S, 



12-15- 



't^Dimmock, G. Anatomy of the mouth-parts and 

 of the suctorial apparatus of citlex. (Psyche, July-Sept- 

 iSSi [7 March iS82|,v. 3, p, 231-241, pi. i.) 



moved hdni liie wing and adhere to the 

 coUodicin. ill order to take impressions 

 of the luuler sides of scales, the latter 

 should be transferred. b\' a process 

 described by Berge,^^ and later bv 11. 

 Landois,^* and others, to a ])iece of 

 paper, and the impression on colloilion 

 then taken from these inverted scales. 

 The process of transferring the scales 

 to paper or other surfaces, first used to 

 get prettily colored figures of butterflies, 

 consists, leaving out details, in gumming 

 the wing of a butterflv upon paper with 

 gimi arabic or glue, and, after tiiorough 

 dr\ ing. removing the wing. lea\'ing the 

 scales attached to tiie paper. From 

 sucii '-butterfly pictures" impressions of 

 the under surface of the scales can be 

 readilv taken. 



By rubbing anilin colors into impres- 

 sions of the striae of the scales of insects 

 I hope later to gain further knowledge of 

 the external configuration of insect scales. 



Fischer, in his dissertation, mentioned 

 that branching or notched hairs seemed 

 a characteristic of the scarahaeidae. 

 and I have only found them in that 

 famih' of coleoptera, although, oiUside 

 of coleoptera, they are not rare (e. g., 

 in BoDihiis and other hymenoptera). 

 Among the scarabaeidae this notching, 

 or covering of the siu'tace of tlie hairs 

 with secondarx liairs. extends also to 

 the scales, ami we have some that, like 

 those of Iloplia. seen in fig. 3 /' and c 

 (p. 10), present the general ajipearance 

 of cactus leaves. 



^-'Berge, T. TasclienbucJi Pur kafer- und scliiiiet- 



terlingssammler - . . Stutli^art, 1S47, p. 55-^12. 



it^Landois, II. Xeuc nietliode schmettcrlinijc zu 

 copiren. (Zeitschr. f. wissensch, zool., iS'Ki, v. 16, p- 

 l.«-l.i-l') 



