586 MODERN CLASSIFICATION OF INSECTS. 
Phthiromyia Zaér.), composed of the single genus Nycteribia (jig. 
133. 14. 15., N. Sykesii Westw.), has the head very small and dorsal, 
not being received into a deep anterior excavation of the prothorax 
(fig. 133. 16. head above, 17. beneath, 18. sideways). The antennz 
are very short and biarticulate. The mouth consists of two large 
lateral setose valves, and a central style, which I found to enclose 
several setae, thus perfectly analogous to the mouth of the Hippobos- 
cide. They have neither wings * nor balancers, but the intermediate 
legs are connected at the base with a pair of strong comb-like organs, 
(fig. 133. 19.), which are the probable representatives of the wings. 
The thorax is flat, and singularly constructed, and the first abdominal seg- 
ment is very short, and on its ventral surface armed with a row of strong 
short bristles (fig. 133. 21. under side of thorax, and base of abdomen). 
The legs are very long, with the basal joint of the tarsi exceedingly 
long and articulated, and the terminal ungues very strong and hooked 
(fig. 133. 20.). The under side of the extremity of the abdomen of 
the male is furnished with two elongated slender incurved appendages 
(fig. 133. 24. N. biarticulata g¢ ); that of the female is destitute of 
exserted organs, except in the last named species, in which there are 
two elongated, clavate, and setose styles (fig. 133. 23.). The only 
species hitherto discovered live upon the bodies of bats, and compose 
the genus Nycteribia Zatr., Phthiridium, Hermann. In my memoir 
on this genus, I described the puparium (fig. 133. 22.), which I had 
succeeded in extracting from the abdomen of a large Indian species 
(N. Sykesii Westw.), thus further proving its relation to Hippobosca. 
I think this the fittest place to notice some anomalous insects of 
minute size communicated to me by J. Hogg, Esq., F.L.S., discovered 
by him inhabiting Spongilla fluviatilis, and respecting whose natural 
relations, and even the order to which they belong, I am in doubt. 

Dufour, in Ann. Sci, Nat. April, 1831 (Nycteribia). 
Guérin. con. R. An. Ins. (Nyet. Westwoodii). 
Hardwicke, Gen. Drawings of Indian Ins. in Brit. Museum. 
HVestwood, in Trans. Zool. Soc. vol. i. (Monogr. Nyeteribia). 
* Such at least is the case with all the hitherto described species. Mr. Mac 
Leay has, however, shown me a species from the West Indies possessing short 
wings. 
