59° 



Color and Pattern and their Uses 



lines or strioc. These striae \'ary in distance apart, on dififerent scales, from 

 .0007 mm., as in the scales of the great blue Morpho butterflies, to .004 mm., 

 as in the sulphur-yellow butterfly, Catopsila cubule. 



The scales cover (in all but the few "clear- winged" moths) the wings 



on both upper and lower sides, 

 being insecurely attached to the 

 wing membrane by ha\-ing their 

 short pedicels inserted in litde 

 pockets or cups on the wing sur- 

 : ce. They show an interesting 

 ■iiid varying manner of arrangement. 

 This arrangement \"aries from an 

 extremely uniform one in the but- 

 terflies and higher moths to one 

 of much less regularity of disposi- 

 tion in the lower moths. On the 

 wings of a butterfly the scales are 

 inserted with their pedicels directed 



, , , toward the base of the wing in 



Fic. 772. — .\ small, partlv denuded part <» , „ , 



the wing of a hutterfy. Z. ww sp., showing subparallel rows runmng trans- 

 the scaJes and pits in a wing membrane, verselv across the wing, i.e., from 



into which the tinv stems of the scales are . •" » _ -.„_•„_ Ji :_ „„j 



inserted. (Photor^crograph by George O. anterior to postenor margm, and 

 Mitchell; greatly magnified.) the scales in each row are at 



appro-ximately equal distances apart. Their distance is less than the width 



of each scale, so that adjoining scales 



o\-erlap laterally and thus make each row 



to be composed of two tiers of scales, an 



upper and an tinder one: the insertion- 

 cups of one tier are very slightly but per- 

 ceptibly ad\-anced beyond those of the 



other tier. The scales of the upper tier 



alternate with thoise of the lower tier, and 



each upper scale o%-er' - ' -lUy twv 



under ones. But in to this 



lateral ox-erlapping;. the distance between 



the rows of insertion-cups is less than 



the leno^th of the scales^ so that there 



is am overiapiptng of the tip of the 



scales of one row o^-er the bases of the 



scales in the t>eTt row in front. By this 



■ c-d a cor- 



^..; ■ ; -— .. _:.ier) of e... 



^OOiAifcy Kut^rii t«<f\l- } 



-.gied covering of scales 



