222 PERCY SLADEN TRUST EXPEDITION 
slightly concave in Paroosternum degayanum but not at all concave in Oosternum 
costatum), and in having the front of the metasternum depressed and sunk beneath 
the posterior margin of the elevated mesosternal area, instead of united with it as in, 
e.g., Oryptopleurum.  Paroosternum degayanum has a marked median longitudinal 
impression on the metasternum: in the specimens of Oosternum costatwm examined 
there is no trace of impression on the metasternum, which is slightly convex; in the 
one specimen of Oosternuwm sorexw which I have seen the elevated median part of the 
metasternum is slightly concave in the middle, but this concavity is quite different 
from the marked longitudinal impression of Paroosternum degayanum. The latter 
has its femoral lines continued to the anterior corners of the metasternum, while in 
Oosternum costatuwm they become obsolete in front. 
23. Puroosternum degayanum, sp. nov. (Plate 14, fig. 22). 
Elongato-ovalis, sat convexus, nitidus, fuscus, palpis antennisque testaceis, harum 
clavis infuscatis, pedibus fusco-testaceis ; capite prothoraceque distincte sat rare punc- 
tatis, hoe serie basali punctorum fortiorum; elytris striis impressis et sat fortiter 
punctatis, interstitiis haud elevatis et tenuiter sat rare punctatis. Long. corp. circa 1 mm. 
The surface is shining, but a very fine reticulation is visible under a compound 
microscope. The pubescence of the upper surface is not easy to see, consisting of 
extremely scanty and fine pale hairs arising from the punctures on the interstices of 
the elytra (in these specimens there are no hairs on head or thorax, but possibly they 
are broken off). The punctures on head and thorax are very distinct but not close: 
the thorax has a regular series along its base, a feature which is also present im 
Oosternum costatum Sharp. The elytral striz are strongly impressed and strongly 
punctate; the interstices finely and not closely punctured, not in the least raised into 
costee or carinze, their median parts being almost flat. 
Oosternum costatum Sharp is much less shining and more strongly reticulated : 
its pubescence is much more conspicuous: its head and thorax are more strongly and 
closely punctured: and the alternate interstices of the elytra are raised into costee. 
Oosternum sorex (Sharp) is much larger than Paroosternum degayanum and quite 
different from it in general appearance. 
This species is dedicated to Mr J. A. de Gaye, F.L.S., who during the time that 
he lived in the Seychelles was a keen student of the entomology of the islands. 
Loc. Seychelles. Mahé: from near Morne Blanc, X.—XI. 1908, 2 specimens. 
Histeridee. 
16 species are here enumerated as occurring in the islands visited by the Expedition. 
The number previously recorded was 8, and of the 8 species now added 5 are new to 
science. The 16 species represent 6 genera (in three of which two subgenera are repre- 
sented). 13 out of the 16 species are actually represented in the collection made by 
the Expedition, while the remaining 3 (Platysoma richtert, Carcinops 14-striata, 
Saprinus erichson) were found only by previous collectors. 
