88 KANSAS UNIVERSITY QUARTERLY. 



ized scales of the LasiocampidcX (see fig. 12), but the teeth of the 

 Parasid scales are never long, as they always are in the Lasiocampid 

 family. 



Family P.vi'omori)liidR> (figs. 12-18, Plate X). This small family 

 comprises but four North American genera, viz., AcoloitJis, Tri- 

 procris, PyyjDiorplia and Harn'sina. The species are few, the total 

 number of North American forms being but twelve. They are all 

 small moths with smoky black wings. The wings are sparsely scaled, 

 those of Harrisina being less thinly scaled than the others. There is 

 little or no evidence of arrangement of the scales into rows, the 

 covering being obviously little specialized. The line of specialization 

 of the scales is well shown in any one of the four genera, the scales 

 throughout the family showing a striking similarity both in generalized 

 and specialized forms. The line of development is as follows: A 

 widening of the hair-form, a splitting of the distal end into two 

 fingers, and a gradual widening and shortening of the scale-blade, 

 resulting finally in a rather narrow, two-pointed, small scale. The 

 points may be rather long and sub-acute, as in the typical specialized 

 scale of Triprocris (see fig. 14, Plate X), or short and acutely- or 

 bluntly-angulated as in Harrisina and PyromorpJia (see figs. 16 and 18, 

 Plate X). In AcoIoitJius the fingers or points are very short and 

 usually bluntly angulated (see fig. 17, Plate X). The scales of Aco- 

 loH litis are smaller than those of the other genera. A typical scale of 

 Acoloitlius falsarius, forewing, measured .068 mm. in length and .02 

 mm. in width. A scale of Harrisina coracina was .112 mm. long, 

 .024 mm. wide, and its stride were .0017 apart. A scale of Triprocris 

 marienii was .120 mm. long and .024 mm. wide. 



The four genera show some variation in degree of specialization of 

 wing-covering, Triprocris possessing the seemingly most generalized 

 covering, then coming PyrontorpJia, Harrisina, and Acoloitlius in 

 order named. 



THE SPECIALIZED FRENAl'^. 



Among the large families of the "specialized Frenatne" the study 

 of the wing-covering becomes more difificult. Certain general con- 

 ditions are noticeable, conspicuous among them being the great abun- 

 dance and the highly-specialized arrangement of the scales among the 

 butterflies. A perfection of even, strict arrangement of the scales 

 into parallel rows and into overlapping tiers in each row is arrived at. 

 To compare the general appearance of an irregular arrangement (or 

 lack of arrangement) and a regular arrangement, figures 2)Z ^^itl 34 are 

 introduced into Plate X. 



Limitations of time and space prevent me from considering in this 

 paper the scale-conditions in the various families of the "specialized 



