KELLOGG: TAXONOMIC VALUE OF SCALES OF LEPIDOPTERA. 87 



is as follows: The hair-form widens, acquiring convex lateral margins; 

 there is then a shortening and widening of the scale, without "finger- 

 ing," and with the greatest breadth at or near the outer margin, until 

 a broad, short sub-pyrainidal or sub-orbicular form is attained, with 

 outer margin rounding truncate or sinuous. This mode of develop- 

 ment holds for Cossus, Hypopta and Ziuzera (Cjss/i/a I have not 

 examined). In Coss/zs the scales may show a slight emargination in 

 the middle of the outer margin thus making two short, rounded, blunt 

 lobes, or there may be two craarginations forming three lobes. But 

 these lobes are caused by an extra prominence of the sinuosity, and 

 appear only in specialized scaler and UDt on the generalized scales. 

 A typical specialized scale from the forewing of Frionoxvsfits robinur 

 was . 152 mm. long and . 120 mm. wide at widest part. 



Family Parasidiv (see figs. 19-29, Plate X). This family is the 

 largest among the generalized Frenats, 13 Xorth American genera 

 being included in it. I have examined specimens representing 

 six of these genera, viz., Euclea, Empretia, Parasa, Isa, 'Toriri- 

 cidia and Liinacodcs. The typical specialized scale is broad and 

 large with six or eight short, acicular points on the outer margin 

 (see 24, 25 and 27, Plate X). The scales contain much less pigment 

 than (\o those in the other families of the "generalized Frenals." 

 They appear comparatively clear and transparent. The small 

 amount of pigment granules present is usually aggregated along the 

 outer margin, in the teeth, along the lateral margins and often along 

 a median longitudinal line. 



The line of specialization, as shown in Eiiclca cippns, shnw=; a 

 widening, especially distad, of the hair-form, the appearance of two 

 and then several short, pointed teeth, accompanied by continuous 

 shortening and broadening of the scale blade. The widest portion 

 of the scale is always at the base of the teeth so that there is a gradual 

 tapering of the scale blade to the pedicel. Often in scales, probably 

 not of the most specialized type, the lateral xiiargins are sub-parallel 

 for some distance behind the outer margin. 



In the scale of the hindwing of Euclea cippus the outer margin or 

 apex of the scale is not toothed but single-pointed (see 28 and 29, 

 Plate X). A typical scale from the base of the forewing of cippus 

 was .224 mm. long and .112 mm. wide, and the strire were .0014 mm. 

 apart. This scale had 7 teeth; the scales of the disc and limb of the 

 wing are hardly as large. 



In Tortricidia fcstacca the scales average smaller than in Euclea, 

 and are proportionally narrower. 



The specialized scales in the six genera examined by me were very 

 uniform in shape and size. They suggest slightly the special- 



