PSYC^HE. 



THE SCALES OF COLEOPTERA. 



KV GEORCE niMMOCK. CAMBRIDGE, 



( Coiithiucd ft 

 GENERAL SUMMARY. 



After the preceding descriptions of 

 some forms of scales among coleoptera, 

 I wish to consider the subject more 

 generallv. First to be considered is the 

 question, in what families of coleoptera 

 ha\e scales been found. Fischer men- 

 tioned scales as occurring in teredvles. 

 clavicornes^ latnellicornes and curcti- 

 //oiiidcs, — or to use the modern equiv- 

 alents for the families in which he found 

 scale-bearing species. — in the cleridae, 

 ptinidae. derniestidae^ byrrhidae, 

 scarahaeidae and ciirciiUonidae. To 

 this list I would add with certaintv the 

 elateridae, basing this addition on the 

 scales of Chalcolcpidiiis and Alans 

 described in this paper. According to 

 mv views of what constitutes a scale I 

 would add fmthcr the cerambycidae. 

 and with some doubt the bitprestidae. 

 The scales of Clytus robiniac de- 

 scribed in this paper, it seems to me. 

 can scarcelv be called hairs, altho to 

 the naked e\e or to a low-power lens 

 they appear like hairs. Thev are too 

 much flattened and the striae end in the 

 manner in which they do in scales. 

 The question whether the sword-shaped 

 appendages of Psiloptera drnn/mondi 



out page 4y. ^ 



are really scales or hairs is less easily 

 settled but I should be inclined, from 

 the arrangement of their striae, to term 

 them scales. The form of scale from 

 Alans is readily seen, by the figure of 

 its transverse section (fig. 7, d), to be 

 too flat to be termed a hair, and this or 

 similar forms are not uncommon among 

 coleoptei'a. 



The question of tiie morphological 

 identit\- of scales and hairs of insects has 

 been long since settled, so that the ques- 

 tion of whether an appendage is a scale 

 or hair has little importance. The ex- 

 tremely minute spines or hairs upon 

 the wings of diptera, hymenoptera and 

 other insects are simpl}' another form of 

 scales. It is only in insects where cer- 

 tain kinds of brilliant coloration have 

 l:ieen developed that one finds scales. 

 This leads to a consideration of how 

 hairs and scales of insects aflect color- 

 ation. They mav simply cover a sur- 

 face of tiie same color as their own ; in 

 such cases hairs mav. according to the 

 angle in which thev stand, their abund- 

 ance or their length, give rise to ap- 

 pearances which we designate as pubes- 

 cent, velvety, pilose, sericeous, etc. ; 

 scales under similar circumstances may 

 give rise to similar appearances, but are 



