10 



angle. The frenulum is single in the male and divided in the 

 female. 



The second feather in some species is widest towards the outer 

 end, which is very oblique, but in others it is of the same form as 

 the third feather. The median vein runs into this feather, giving 

 off vein 2 which ends in the hind margin, vein 3 which ends in the 

 anal angle of this feather and vein 4 which ends in the apex. In 

 the narrow, tapering forms vein 4 is wanting and 3 runs to the 

 end of the feather. The cross vein and also veins 5 and 6 are 

 exceedingly fine and scarcely visible under the mosl^ favorable 

 circumstances. 



The third feather tapers gradually to the more or less blunt 

 outer end, but in some species it has a very obtuse and rounded 

 angle on its hind margin, which represents the anal angle of the 

 wing (Plate II., fig. 2). This feather has a strong vein running 

 through the middle to the end, which is undoubtedly vein Ib. In 

 some species a weak vein may be seen above lying very near the 

 edge of the feather, and in others a shorter vein below running to 

 the hind margin of the feather a little beyond the anal angle. 

 This, without doubt, is vein la, and therefore the three internal 

 veins are represented in the Pterophoridse, but all three do not 

 occur in any one species. 



The fringes are long and arranged along both sides of the 

 feathers, giving them a strong resemblance to the feathers of a 

 bird, thus making more complete organs of flight. In some 

 species there are clusters of dark spatulate scales in the hind 

 fringe of the third feather, and similar scales occur along the 

 median vein on the under side of the wing. The basal part of 

 the median vein on the upper side of the hind wings is not pro- 

 vided with a row of fine hairs, as in some families of moths. 



The head is of medium size, with the front smooth and vertical 

 in some species but more or less conical in others. The labial 

 palpi are either porrect or curved upward and closely scaled, or 

 more or less bushy. The maxillary palpi are entirely wanting. 

 The proboscis is about as long as the head and thorax, and not 

 clothed with scales at the base. The eyes are nearly hemispher- 

 ical, naked and without lashes or cilia. The ocelli are absent. 

 The scales of the head lie smooth over the surface, giving it an 

 even appearance ; but in some species they form a more or less 

 cone-shaped tuft, extending forward from the front. The antennae 

 are fine filiform, and about two- thirds as long as the costa of the 

 fore wings. The basal segment is much larger than those beyond, 



