INTRODUCTION 



9 



In the fore-wing the first nervure is a stout rib emanating from the base of the wing 

 and extending some distance along the costa. This is the costal nervure and is without 

 branches. Beneath this, and in close proximity, arises the subcostal, which usually gives 

 off five branches, though in some cases a smaller number may be present. The last two 

 branches form a kind of fork which stiffens the apex of the wing. Beneath is given off the 

 median nervure which always has three branches. The distal ends of the subcostal and 

 median nervures are united by two or three small cross nervules called discocellular, and 

 designated respectively the upper, middle, and lower. The first is often much reduced, in 

 some cases almost obsolete, and in others absent. The lower discocellular nervule is frequently 

 absent or very rudimentary, especially in the hind-wing, the space between the subcostal 



c, Costal nervure; sc., subcostal; sc. i, 2, 3,4,5, branches of subcostal; u.r., upper radial; l.r., lower 

 radial; m. i, m. 2, m. 3, branches of median; s.m., submedian ; p.c, precostal; mdc, middle discocellular; 

 UDC, upper discocellular ; ldc, lower discocellular ; D., discoidal cell ; i., internal. 



In the hind-wing UR. is the second branch of the subcostal in English nomenclature. 



and the median, called the discoidal cell, being in these cases open at the distal end, a very 

 noticeable feature in many genera. The area from the discoidal cell to the hind-margin 

 is supported by two branches called the discoidal or radial nervules, which have been con- 

 sidered to be branches of a formerly existing discoidal nervure. Beneath the median is an 

 unbranched nervure extending from the base to the hind-margin and known as the submedian. 

 Beneath the submedian is a small nervure called the internal. This is a variable charac- 

 teristic, being well developed in the genus Papilio, joined to the submedian in Danaida, and 

 absent in the great majority of other genera, including Hypolimnas. In the Papilionidae and 

 Morphinae there is a small branch (in the fore-wing only) called the interno-median nervule. 

 It joins the median and submedian nervures near the base. In the hind- wing the principal 

 features are repeated but with some modifications. The costal corresponds to that of the 



1200 B 



Genus Amauris. 



