MR. J. O. WESTWOOD ON NYCTERIBIA. 281 
mediate legs the corresponding process is also detached, being affixed to the internally 
elongated trochanter at its base: it is horny, lunate, and very small, and externally 
armed with about sixteen obtuse teeth, directed upwards and backwards. This organ 
was first noticed by Hermann, by whom it was figured. Mr. Curtis thus describes 
it: “Wings none, but there is a narrow appendage ciliated with short strong bristles, 
on each side at the base of the middle pair of legs ;” adding, that these ciliated ap- 
pendages ‘‘ may cover spiracles for breathing, organs for hearing, or they may be the 
analogue of rudimentary wings.” That the latter of these suppositions is correct, I 
feel induced to conceive, notwithstanding their extraordinary form and our ignorance 
of their uses, from their situation and evident attachment to the internal base of the 
intermediate legs. The supposition that they are organs of hearing seems to have 
arisen from the supposed want of antenne, and cannot therefore be maintained, as those 
organs exist ; while the idea that they may be connected with spiracles for breathing 
requires more notice, from having been entertained both by Latreille and M. Dufour, the 
latter of whom has entered at some length into the reasons which have induced him to 
adopt such idea: these consist, 1. in the position of this pectinated organ; 2. in the 
asserted absence of any other point which might be considered as a respiratory orifice ; 
and 3. in the evident analogy between Nycteribia and the Hippoboscide. Now although 
the first of these reasons is certainly in favour of such opinion, the latter two are in- 
correct, the abdomen, as will subsequently be described, being furnished with a series 
of spiracles, and the thoraz itself exhibiting a pair of minute oval points, which appear 
to me to be evidently spiracles, and which exist in the elevated crustaceous ridge be- 
tween the central and anterior lateral portions of the thorax, immediately behind the 
insertion of the head, which organs I have noticed not only in Colonel Sykes’s 
insects, but also in my Chinese species. As to the analogy existing between Nyc- 
teribia and the Hippoboscide, it is to be observed, that from the totally distinct organi- 
zation of the thoraz it is difficult to trace the situation in Nycteribia which is analogous 
to the position of the spiracles in the Hippoboscide. ‘These, it is to be observed, vary 
in their location ; but in none are the anterior pair placed between the anterior and in- 
termediate legs, as are the pectinated processes in Nycteribia, but, on the contrary, in 
a higher and more dorsal position, which would probably occur in Nycteribia nearer 
the base of the head!. 
The legs offer several remarkable peculiarities: they are very long and strong, and 
'M. Dufour has proposed the employment of the position and structure of the spiracles as affording cha- 
racters, “aussi solides que faciles 4 explorer,” for the establishment of families and genera, and has given an 
account of their structure in the Pupipara. That they would afford solid characters cannot be questioned ; 
but some notion may be obtained of the difficulty attending their adoption, when it is stated that M. Dufour 
has overlooked the entire series of abdominal spiracles of the Hippoboscide. See Lyonnet’s Posthumous Re- 
searches, pl. 1. f. 2. & 3. 
