KELLOGG: TAXONOMIC VALUE OF SCALES OF LEPIDOPTERA. 59 



tip. The insertion cups are practically identical with those found 

 among Lepidoptera, goblet-like in form. Mystacides puiiiiata has, 

 in addition to the usual scale-hairs, about .i mm. long and .005 mm. 

 wide, opaque, striated and slightly curving, the limbal area of the 

 forewing sparsely dotted over with certain conspicuous, balloon- 

 shaped scales (see figs. 5, 6 and 7, Plate IX). They are white, with a 

 granular content, finely striated, and average about .0736 mm. in 

 length and .00S6 mm. in width at the widest part. They are not 

 flat, but flattened bulbous, and strongly suggest an identity with the 

 androconia, or scent scales of the Lepidoptera. 



The scale-hairs of the Trichoptera are more abundant on the limbal 

 than on the basal area of the wing, and exhibit no arrangement in 

 regular rows or tiers. In some species they are numerous enough to 

 compose a rather complete hairy covering or sheath over the wing. 



The scale-hairs in many forms are little or not at all flattened, but 

 are sub-cylindrical, tapering to a point. There is in these scale-hairs 

 but .slight distinction between pedicel and body of the scale-hair, 

 and the greatest width or diameter of the scale-hair is at its base. 

 A cross-section of such a scale-hair showed elevated ridges or stride 

 over the whole surface. 



Such unflattened scale-hairs are fcAind also among the Mecoptera 

 together with the covering of fine, fixed hairs. In Panorpa sp. the 

 fore wing is uniformly covered with fine, fixed hairs, little if any 

 longer on the limb than on the basal area of the wing and no more 

 abundant. There is also a sprinkling of much longer tapering, sub- 

 cylindrical hairs, thickest at the b.ise and without distinctly set off 

 pedicel (see fig. 2, Plate IX). These hairs are insertetl in a sort of 

 socket, and rise nearly at right angles wiih the wing. These inserted 

 hairs are not present on the basal one-foutth of the wing. There are 

 less than one-tenth as many of these inserted hairs as of the fine, 

 fixed hairs. The inserted hairs are situated about. 065 mm. apart, 

 and the fine hairs about .013 mm. apart. Tne inserted hairs are not 

 found near the veins, but only in the central portions of the cells of 

 the wing, there being a considerable space on either side of a vein 

 which is free of inserted hairs. On the veins themselves, however, 

 there are stiff inserted hairs in single rows, tlie hairs in the row at 

 intervals of .053 mm. The inserted hairs are from .06 mm. to .12 

 mm. long, and show faint indications of striation; the fine hairs are 

 about .02 mm. long. On the hind wing the inserted hairs do not 

 appear on the basal third of the wing and in very small number on 

 the middle third; they are not common exce[)t on the extreme limb 

 of the wing. 



It is of interest to note, as bearing upon the strengthening function 



