THE SPECIES OF THE GENUS IXO OF LEACH. 101 



terminal joint has no appendage ; when carefully denuded of 

 scales one finds quite at the end a small knob-like projec- 

 tion. In the species of the second group the pectinations of 

 each joint grow together in broad lamellae, which at first are 

 always notched in the middle, which notch is always de- 

 creasing and disappears on the penultimate joint — the termi- 

 nal joint is a very flat, roundish cone. Moreover these 8 — 

 10 terminal joints, which form the so-called terminal club, 

 are not connate, but only lie very close together. Indeed, it 

 alw^ays remains a question of comparison, if we term the pec- 

 tinations of one or the other species more or less appressed, 

 although their approximation truly in some species appears 

 to be tolerably constant. But in dead specimens the pecti- 

 nations may be spread out artificially, and this may still 

 more readily occur in living specimens; and I have indeed 

 observed some specimens in which the pectinations on one 

 antenna were much closer together on one side than on the 

 other. Also, the statement, that the pectinations are thick- 

 ened at the end, is relative, since in the same antenna the 

 middle pectinations may be quite differently formed from 

 those towards the apex. 



I now proceed to the species of the first group, in which 

 I include all those of which the male antennse end in a 

 point (are pectinated to the tip). 



These species I divide into three groups, of which the cha- 

 racters however are only very superficial, and should only 

 serve for the readier arrangement of them. They are as 

 follows : — 



a. Species with very dark anterior wings (Group of 

 Prunx), 



h. Species w^ith brightly-coloured anterior wrings. 



a. Anterior wings narrow, of nearly uniform breadth. 

 The pectinations of the antennae of $ lie very close together. 



