KELLOGG: TAXONO.MIC VALUE OF SCALES OF LEPIDOPTERA. 



Fit 



Scales from forewius of Megalopijge sp. 



point, .208 mm.; its widtli from tip to tip of tlie two lateral fingers is 

 . 104 mm. 



Family P.s.voiiids« (figs, i-ii, Plate X). This family, as recently 

 revised, comprises five North American genera, viz: Psyche, Pseudo- 

 psycJic, Platoca'tictis, Thyridopterxx and Oiketiciis. The genera Lacoso- 

 iiia and PcropJiora, included in this family in Smith's Tist, * are far 

 removed, by venation, from this family. These five genera include 

 but 10 North American species, the forms being but a remnant of 

 what was once probably a considerable grou]). The Psychids are winged 

 only in the male sex, the wingless female remaining in the sack 

 which it inhabited as a larva. 



I have been able to examine the wing-covering in four of the five 

 North American genera, and the correspondence in scale specializa- 

 tion is obvious. The wings are sparsely scaled (in Thyridopteryx the 

 scales are disappearing, the wings being mostly clear and unsealed), 

 and there is little arrangement of the scales into rows. The special- 

 ized scales in the family are small, narrow, strongly pigmented, 

 usually with two short points (as in T/iyridopteryx and Pseudopsyche), 

 sometimes with three short teeth (as in Pseudopsyche) or with one 

 point (as in Psyche and Oiketiciis'). The line of specialization is as 

 follows: The hair-form shortens, widens, and divides at the tip into 

 two very short points, wliich persist or disappear during the contin- 

 ued shortening and widening of the scale. The points are acute, and 

 never more than one-fifth the length of the whole scale. The strire 

 average about .002 mm. apart. 



"Smith, Joliu B., List of Lepidox^teraof Boreal America, 1891, Philadelphia. 



