288 MR. J. O. WESTWOOD ON NYCTERIBIA. 
as respects the sexual characters, in a manner completely different from that of any of 
the other species, and that those individuals which exhibit the least traces of abdominal 
articulations are females. 
It would seem that Montagu was induced to regard the externally styliferous speci- 
mens as males, not only from the existence of these styles, which he evidently regarded 
as masculine organs, but from the larger, tumid and ovate form of the abdomen of the 
other specimen, which he conceived to be a female. The latter circumstance, however, 
is visible in the specimen at the British Museum, and may easily be accounted for by 
supposing that the other specimens are females in an unimpregnated state. 
It is also to be observed, that in the females of Nyct. Latreillii we have seen that the 
structure of the terminal portion of the abdomen exhibits somewhat of an incipient ap- 
proximation to that of the styliferous abdomen of the female of Montagu’s species. 
Dr. Leach’s specimen of Nyct. Blainvillii, preserved at the British Museum, is evi- 
dently a male: it has the abdomen of an elongated conical form, exhibiting five trans- 
verse series of bristles, and having the terminal joint somewhat larger than the pre- 
ceding, with the extremity truncate and the angles not acute. Being gummed down 
upon paper, I could not examine its under side. 
Mr. Royle’s East Indian species is a male, having an elongate-conic abdomen, truncate 
at the tip, and with the under side of the terminal segment furnished with two incurved 
styles. 
In conclusion, I beg leave to offer the following synopsis of the species, first pre- 
mising, that in all probability, as in the Pediculide, the species are much more numer- 
ous than has hitherto been supposed; and that the accounts given by early authors are 
so deficient in minute precision that it is impossible to decide as to the species described 
by them. For this cause, as well as on account of its being applicable to the whole 
genus, I have followed the example of Dr. Leach in rejecting the specific name of Ves- 
pertilionis. 
1. Nycrerrpia SyYKESII. 
Nyct. rufo-picea, thoracis tegumento dorsali abdomineque obscure albicantibus ; hoc tuber- 
culis minutissimis nigris undique tecto quorum quatuor majora in quadrangulo cen- 
trali disposita, segmentis (unico basali excepto) destituto, apice pilis rigidis ferru- 
gineis elongatis obtecto ; pedibus elongatis, subcompressis, paullo dilatatis, breviter 
setosis, femoribus magis ferrugineis, coxis anticis elongatis tibiisque apicem versus at- 
tenuatis ; pectinibus thoracis elongatis ; oculis e tuberculis quatuor compositis. (*) 
Long. corp. lin. 22. 
Hab. in India Orientali. 
Mus. Dom. Sykes. 
Species maxima. 
