228 REVISION OF THE FAMILY EUSTHENIIDAE (ORDER PERLARIA). 



The form of the superior appendages of the male (Text-fig. 3, sa), and 

 also of the basal joints of the eerci (c), are valuable specific characters in the 

 Eustheviinae. Unfortunately, females are more commonly met with than males, 

 and my series of the latter is so incomplete that I am unable to use these char- 

 acters in the Key to the species. I have, however, given a description of them 

 undei' each sejiarate species, where the males are known to me. 



Key to the Genera. 



Wings short and very broadly round at apices, the amplitude of the hindwings 

 very great. Forewing with a very strong reticulation of pale main veins and 

 cross-veins on a darker ground; the costal series of veinlets abundant, with- 

 out any break after the humeral veinlet Eustheniopsis, n.g. 



(Genotype, E. venosa, n sp.) 



Wings longer, less broadly rounded at apices, the hindwings more subtriangular in 

 shape. Forewing with the pale reticulation either less strongly developed or 

 entirely absent; the costal series of veinlets much fewer in number and more 

 widely spaced, especially after the humeral veinlet, where there is usually a 



more or less lengthy gap Eusthenia Westwood 



(Genotype, E. spectabilis Westwood.) 



Genus Eusthenia Westwood. (Plates xi. — siii.. Figs. 2 — 6.). 



Characters as given in the generic key above, to which may be added tlie 

 following: — Antennae somewhat shorter than the forewings, the basal joint 

 enlarged. Costal space of forewing slightly widened basally, the costal veinlets 

 widely spaced basally, but closer together distally ; usually there is a considerable 

 gap between the humeral veinlet and the next costal veinlet, which is frequently 

 placed nearly up to the level of the origin of Rs. In the hindwing, the costal 

 space is not noticeably widened, and there is always a long gap between the 

 humeral veinlet and the next costal veinlet. In the forewing, M diverges from R 

 at about one-third from base, Rs from R at about half-way; Rs has three 

 or four branches. M.--, is well developed in both fore and hind wings, and forms 

 a well marked cubito-median Y-vein with Cui, the two arms of the Y being gener- 

 ally about equal in length. Cm in forewing has either two or three distal 

 branches arching up anteriorly from the line of the main vein itself: Cu2 lies 

 entirely in the anal furrow. Forewing with three anal veins, usually unbranched. 

 In the hindwing, Rs is fused with M basally for a very short distance in tlie 

 region of the origin of Mr,; Rs has either two or three branches; Cui is simple. 

 lA is weakly formed, and lies very close to Cns, with which it is almost fused at 

 about the middle ol' its length. 2A forks near its origin, and again at or before 

 half-way. 3A sends five or more straight l)ranches into the anal fan, which oc- 

 cupies more than half the total breadth of tlie wing. Cerci long, many-jointed, 

 varying from somewhat longer to somewhat shorter than the length of the abdo- 

 men. 



Genotype, Eiiffthenia spectabilis Westwood. 



Key to the Species. 



1. Wings rich purple. e.Kcept only the large whiti.sh lunula on the forewing and 



the red basal third of the hindwing E. ros/a/is Bks. 



Wings mostly dark greyish or blackish; purple only along costa of forewing: 

 basal portion of hindwing red 2 



2. Lunule of forewing broad, from 2, .5 mm. to 4 mm. wide, its basal border not 



usually as distinctly formed as its distal 3 



Lunule of forewing narrow, from I mm. to 1..5 mm. wide, with both basal 

 and distal borders clearlv defined 4 



