xii 



INTRODUCTION. 



by the anterior margin and the posterior, is called the anterior an- 

 gle, D, on the secondaries; on the primaries, this angle is called 

 the apex; the angle between the posterior and interior margins E, 

 is called the posterior angle on the primaries, and the anal angle on 

 the secondaries. In many of the Tineidae, the interior margin and 

 posterior angle are wanting, because the wings are very narrow 

 and lanceolate, the edge proceeding in a regular curve from the 

 apex to the base, figs. 27, 28. 



The external limit or boundary of the wing is the Unea limbalis, 

 the scales extending beyond that are called the fringe, cilice, fig. 

 20, F. In some micro-lepidoptera, especially in those with narrow 

 wings, these cilice are hair form and very long, and often longer on 

 the secondaries than the breadth of the wing. A line of darker 

 shade, parallel with the margin, often runs through the fringe. The 

 margin is straight, rectus, when it proceeds in a straight direction ; 

 curved, when it forms a concave curve towards the base, fig. 20 ; 

 sinuate, when it makes a convex curve towards the base, fig. 24 ; 

 entire, when it forms an even, straight, curved or sinuate line, fig. 

 24 ; undulate, when it makes small rounded indentations, fig. 20 ; 

 dentate, when there are sharp, angular, closely connected, teeth- 

 like projections, fig. 21 ; cucidlate (hood shaped) when small, 

 rounded emarginations run into sharp angles toward the base, and 

 lobate, when these emarginations are larger, fig. 23. 



. 22. 



Fig. 23. 



1'ig-. 24. 



lb 



The wings themselves consist of a skin-like membrane which are 

 held in a state of expansion by the ribs or nerves, costce, running 

 across or through them. The structure and arrangement of these 

 costce are of great importance in the systematic division of butter- 

 flies, and hence a special description of this structure and the de- 

 termination of each costa are necessary, figs. 22 28. 1 



1 [This nervular system of classification is of comparatively recent date, 

 and is not closely followed in the present work. M.] 



