162 MR. J. O. WESTWOOD ON THE LEPIDOPTEROUS 



acute point from which a single branch is emitted, which forks into two branches, b 3 

 and b 4, b 5 and b 5* arising together from the hind margin of the cell at three fourths of 

 its length from the base. C. mygdon (PL XXVIII. fig. 7) and C. inca agree with C. La- 

 treillii in this respect. 



Among the Helicoinoid species with elongated fore wings, forming the genus Gazera, 

 Boisduval, C. cononia (PI. XXIX. fig. 8) has a small postcostal cell, the 2nd branch of 

 the postcostal vein arising shortly before its extremity ; the 3rd and 4th branches arise 

 from its extremity a little distance apart, the short transverse branchlet connecting 

 b 5 with bh* springs close to the emission of b 5 from the postcostal cell ; the 5th branch 

 arises from the postcostal cell nearly opposite the base of the 2nd branch, and appears 

 to extend backwards to the origin of the 1st branch of the postcostal. The branches 

 b 5* and c 3* extend backwards, forming an acute angle within the discoidal cell, and 

 emit a branch-like fold (discoidal nervure) towards the base of the wing ; c 3 likewise 

 is extended backwards, uniting with this discoidal nervure, forming with it a rudimental 

 (postdiscoidal) cell. 



In C. equadoria (PL XXVIII. fig. 10) the arrangement of the postcostal branches 

 agrees with C. cononia, except that the little transverse vein uniting branches b 5 and 

 b 5* is rather nearer the base of the wing. 



In C. mimica (PL XXIX. fig. 11) and C. linus (PL XXIX. fig. 9) the postdiscoidal cell 

 is also present ; but it only emits one branch at its acute extremity, which forks at some 

 little distance beyond the cell into the two branches b 3 and b 4. 



In C. truxilla (PL XXVIII. fig. 12), on the other hand, the postdiscoidal cell is not 

 completed, there being no connexion between the branches 6 3 and §4; the relative 

 position of the postcostal branches is otherwise identical with that of C. limns. 



In C. Marcel Serresi (PL XXIX. fig. 2), forming the type of Boisduval' s genus 

 Ceretes, the small postdiscoidal cell is present, emitting the branches b 2, b 3, b 4, and 

 b 5 from its extremity at small distances apart, and the short transverse veinlet con- 

 necting b 5 and b 5* (and closing the discoidal cell d c) from its hinder margin beyond 

 the middle. The discoidal cell is traversed by a longitudital vein-like fold, the hinder 

 portion of the cell (d c*) forming a distinct cell by the addition of a veinlet extending 

 backward from the basal junction of the median branches c 3* and c 3 — thus leaving 

 a narrow tract between it and the basal portion of the median vein c, which may be 

 called the premedian cell, p.m. c. 



In C. chremes (PL XXIX. fig. 4) the arrangement is nearly similar ; but the vein-like 

 fold in the discoidal cell is less strongly defined, and the little transverse vein which 

 closes the discoidal cell does not arise from the hind margin of the postcostal cell, but 

 is pushed forwards and arises from the 5th postcostal branch close to its base. 



On comparing the figures of the wings of C. cacica (PL XXVIII. figs. 6 and 6 a) with 

 those of C. Marcel Serresi (PL XXIX. figs. 2 and 3), it will be seen that the general 

 arrangement both of the veins and cells is identical. 



The arrangement of the veins of the hind wings has been comparatively neglected in 

 the Lepidoptera, although Dr. Boisduval has partially, but not satisfactorily, used this 

 character in the generic distribution of his Castniaires. In the vast majority of the 



