500 Mr. G. Ne\\^ort on some new Genera of MjTiapoda. 



at their ajiex, with the internal margin acute and denticulated, and 

 the basihir joint encroaching on the dorsal surface of the basilar 

 segment. Sub-basilar segment large, transverse, with the anterior 

 margin straight, and the posterior and angles rounded. Body gra- 

 dually tapering ; legs from forty-five to seventy pairs ; posterior pair 

 styliform. 



Species 1. Mecistocephalus ferrugineus, Koch. 



2. Mecistocephalus maxillaris, Gervais. 



3. Mecistocephalus punct if rons, Newport. 



Frontal segment and mandibles deeply punctured, with the basilar 

 segment and labium dark chestnut ; body testaceous, mandibles each 

 with two large acute teeth ; legs forty-nine pairs. 



Length two inches three-tenths. India : — Elliot, Esq. 



In the collection at the British Museum. 



Frontal segment polished, with small scattered punctures ; man- 

 dibles very strong, polished, and deeply punctured on the superior 

 surface, with the internal margin acute, with two large sharp teeth ; 

 labium flattened, polished, with a longitudinal depression, and a few 

 minute, scattered punctures ; body gradually tapering, but broad and 

 strong anteriorly ; legs forty-nine pairs, broad, strong. 



I am uncertain whether this specimen had arrived at its full 

 growth, the number of legs being less than in the other species. It 

 may nevertheless have acquired its proper number since the species 

 described by M. Gervais has but forty-six pairs, and I have ascertained 

 most satisfactorily that the whole of the Chilopoda acquire very nearly 

 their full complement of legs before they have attained to one half of 

 their adult size. 



4. Mecistocephalus Guildingii, Newport. 



Frontal segment polished, with a few scattered punctures ; sides 

 and posterior angles rounded, ferruginous ; mandibles quadridentated ; 

 basilar segment and labium polished, ferruginous, with a broad, lon- 

 gitudinal sulcus and deep punctures on the latter ; body yellowish, 

 testaceous ; legs forty-nine pairs. Length one inch and a half. 



Island of St. Vincent. Rev. Lansdowne Guilding. 



In the cabinet of the Rev. F. W. Hope. 



There are live specimens of this species, varying considerably in 

 size, but agreeing most accurately in the number of their legs. 



5. Mecistocephalus punctilahiuni, Newport. 



Head, mandibles, labium and sub-basilar segment ferruginous ; 

 mandibles tridentated ; body brownish-green, with the two posterior 

 segments antennae and legs ochraceous. Frontal segment and la- 

 bium flattened, the latter deeply, and thickly punctured. Legs sixty- 

 one pairs. 



Length two inches. Country ? 



In the collection of the British Museum. 



The frontal segment of this species is flattened and punctured, 

 with the posterior margin straight, and the anterior somewhat 

 rounded ; the mandibles are smooth, polished, rather straightened, 

 and rounded, with the internal margin less acute, with two or three 

 very small teeth ; labium flattened, polished, with large, numerous 



