KELLOGG: TAXONOMIC VALUE OF SCALES OP LEPIDOPTERA. 



scale, which continues shortening and widening, the point of greatest 

 width coming nearer and nearer to the distal end of the scale. By 

 this there results a more truly spatulate shape. The culmination of 

 specialization is reached in a short, broad scale with rounding trun- 

 cate outer margin, the scale being widest at its outer margin. 



'POi-ializea 



L 2. 3, 4 and b. scales from a siiiKlf' hiiuUviiif; of Prioiioxystii-; robini 

 scale from forewiiiy; of same moth. 



The outer margin is entire, no fingers or teeth appearing anywhere in 

 the course of development. This outer margin is sometimes, in the 

 specialized scales usually, gently and unevenly sinuate: in Cossus 

 there is a shallow, rounding emargination at the middle of the outer 

 margin so that the rest of the margin appears as two short, bluntly- 

 rounding points or teeth. There may even be two emarginations so 

 that three rounding teeth are formed. But these emarginations are a 

 modification of the sinuation which appears late in the course of the 

 scale's development and the " teeth " of the Coss//s scales offer no 

 reason for likening the scales of Cc?ssus with those of AFcgalopycre. 

 The transition forms of the scales of Cossidoi are illustrated in figure 

 II, all the scales figured having been taken from a single hindwiny of 

 Prionoxystiis robiniic. 



Still another line of scale specialialization is that sliown in Glovcria, 

 and with certain modifications to be hereafter noted, pretty fairly 

 characteristic of the family Lasiocampida^. The scale-hair becomes 

 a little flattened and widened; then it divides at its distal end into 

 two fingets, the cleft not extending very far along the length of the 

 scale; a shortening of the proximal portion of the scale and a widen- 

 ing of that part of the scale between the pedicel and the base of the 

 two fingers is next apparent. Then one of these fingers divides near 

 its base and a third finger is formed which grows out to be as long as 



