284 



FIRST LESSONS IN ZOOLOGY 



firmly, to the wing membrane by their stems, and arc 



arranged in fairly even rows. 



Fl,;. 



-Tiit of rifnuded wiii^^ of a 



In each row they are so 

 thick that they overlap 

 each other's sides, and the 

 rows are so close together 

 that the tips of the scales 

 of one row overlap the 

 bases of those of tlie one 

 in front. This arrange- 

 ment is much like that of 

 shingles on a roof, and 

 each wing is thus shingled 

 above and below (fig. 223) 

 by thousands of tin}' scales 



upper and lower sides, and tliree 

 scales. (From specime]!. ) 



ln.tterfly,(>„/A,t'reatly magnified, ^^,j^;^,j^ produce all itscol- 

 lo show rl")W^ of insertion pits on '■ 



ors and markings. These 

 colors are made in two 

 \\'a}'s ; either the scales are actually brownish or reddish 

 or 3'cllowish or black themselves because they contain 

 pigment granules inside, or else they reflect white light in 

 such a ^\'a3' that it is broken up, as by a prism, into colors, 

 only some of which reach our eyes. The metallic and 

 iridescent l<inds, the greens, blues, coppers, purples, etc., 

 all of which change somewhat as we change the position 



Fk;. 223. — I)iaL^ram (o show sln'iii^din^ arrriiiL^'ement of scales over suriacc 

 of butti-Tlly's \\'iiig; the sliorl black bars indicate scales in cross-section, 

 the broad centi-al bar, tlie wiriL,^ in cross-section. 



of our eyes, arc produced in the second wa}-. The duller 

 and the fi.xcd colors, such as the reds, 3'ellows, browns, 

 etc., are produced by scales containing [ligments of the 

 same shade. 



