KELLOGG: TAXONOMIC VALUE OF SCALES OF LEPIDOPTERA. 6 I 



and hind wings on their upper and lower sides are sparsely covered 

 with fine, curving, pointed, short hairs not inserted in sockets or 

 "insertion cups," as are the scales, and not easily rubbed off. These 

 hairs average .005 mm. in length, and are distant from each 

 other at their bases a length approximately equal to the length of the 

 hairs. The scales of luiiiiiacule/la average from .1 to .15 mm. 

 in length. In Hepialus sylvinus (see fig. 3, Plate IX), the wings are 

 similarly covered with fine hairs, averagini; from 02 to .03 mm. 

 in length. The scales of sylvinus are from .2 to .3 mm. long, 

 or about ten times the length of the fine hairs. 



Beyond the availability of the presence of the fine hairs in the 

 Jugatae and their absence in the Frenatce as a recognition character* 

 the phylogenetic significance of this character seems to me of interest, 

 and especialiy so in the light of Professor Comstock's recognition of 

 two main divisions of the Lepidoptera. The Jugatre, according to 

 Professor Comstock, are the more generalized group of the two sub- 

 orders. The venation indicates this strongly; Microptcryx possesses 

 the most generalized mouthparts to be found among Lepidoptera; 

 and, lastly the mode of tying the wings together is the same as obtains 

 in many of the Trichoptera, a group of insects offering many indica- 

 tions of affinity with the Lepidoptera. In addition to these indica- 

 tions, or, indeed, demonstrations, of the generalized condition of the 

 grou]) JugatK, the correspondence of the essential features of the 

 wing- clothing of the Jugatai and the Trichoptera suggests anew the 

 generalized condition of the Jugata\ The figures in Plate IX (see figs. 

 I, 2, 3 and 4) of the clothing of the wings of Alicroptciyx, Hepialus, 

 Ncui-ouia and I\inorpa, are drawn to the same scale, and indicate 

 the relative size and abundance of the fine hairs and the scale hairs 

 among the four groups. The wing-covering of the Jugatae is more 

 specialized than that of the Trichoptera in two ways: (a), by the 

 reduction in size, the degradation, of the fine hairs, tending toward 



*The torm "recognition character,'" u=ca here and In the diagnoses of the suborders, 

 may need a note of explanation. Professor Comstock refers to such characters as fol- 

 lows, in his essay iloc. cit,) : '■ There will also arise, 1. believe, in a work of this kind a 

 necessity for distinguishing between the essential characters of a group and those 

 characters which are used by the systematlst merely to enable students to recognize 

 members of the group. For it seems to me that the essential characters of a group of 

 organisms do not lie necessarily in the presence or absence of any structure or structures, 

 or in the form of any part or parts of the body of the living members of the group: but 

 rather in the characteristic structure of the progenitor of the group; and in the direction 

 of specialization nf thi' ilc^ctMidants of this progenitor. 



•' Thus, to use amiiii tli.- illii^tratinn given above, tae JugatEe are essentially character- 

 ized as the desecn.lam- (il those ancient Lepidoptera in which the wings of each side 

 were united by a juguiii; iiud they are also characterized by a tendency towards an equal 

 reduction of the ve us of the two pairs of wings. While the Frenatae are essentially 

 c laraeterized as the descendants of those ancient Lepidoptera in which the wings of each 

 side were united l5y a frenuliim; and they are also characterized by a tendency towards 

 a greater rediictlDU of the veins of the hi ad wings than of the forewings, or, in other 

 words, l)v a t ndeucv towards a cephahzation of the powers of flight. The fact that in 

 manv of the Frt-nat-.p the Irenuluin has been lost, does not invalidate in the least the 

 truth of the characterization. The lo-s of the frenulum, however, in certain Frenatffi 

 renders necessary the use of sonie other character or characters by the systematists as 

 recognition characters." 



