TORTRICINA. 153 



exist t'lsewhere among Lepidoplera except in a few butter- 

 flies, is iu the present group ratlier extensively developed, 

 and has been used as a valuable structural character for pur- 

 poses of classification. It is, however, a character belonging 

 exclusively to the male sex, and is distributed in a singularlj' 

 arbitrary manner. It is known as the costal fold ; a small 

 portion of the costal margin from the base being extended, 

 dilated, and folded back, exactly in the manner of the lapels 

 of a gentleman's coat. In some species the fold is broad, 

 and causes an interruption in the symmetry of the costal 

 margin ; in others it is narrow and verjr straight, and even 

 becomes, in some species, so obscure as only to be seen by 

 the aid of a lens. Eut should it by any accident be disturbed 

 and raised, it is most conspicuous, and is seen to have nothing 

 of the colour of the upper side of the wings on its under 

 surface, but to have instead a shining greyish or white gloss, 

 and instead of the short scales of the upper side, to be fui-- 

 nislied with pale hairs laid longitudinally. It is placed 

 always quite outside the subcostal nervure. 



This character, if used to separate a family, has the 

 effect of cutting squarely across other reliable characters, and 

 of dividing small groups which to the ordinary judgment 

 appear to be most closely allied together, and I have 

 thought it best to use this costal fold merely as a useful 

 (jeneric character. 



The^;/rt)i, of mnrkiiujs, hitherto so useful in descriptions, 

 has in this group partly disappeared, or has been trans- 

 formedo The basal line, moved outwards, is now usually no 

 definite line at all, but the margin of a large basal blotch. 

 Similarly the first and second lines have become simply the 

 inner and outer margins of a more or less distinct central baud, 

 and at the costal origin of the subterminal line is now com- 

 monly a flattened subovate costal spot, from which often an 

 irregular thread lies along the hind margin. Of the stig- 

 mata, or central or discal-spot, there usually is seen no trace, 

 though iu a few species a spot lies in the apex of the discal 



