SCOTT—COLEOPTERA; HYDROPHILIDA, HISTERIDA 215 
and much blunter, so that there is no sharp central carina (Pl. 14, fig. 20).] Basal 
abdominal segment without a carina. Tarsi (Pl. 14, fig. 19) nearly as long as the tibie, 
hirsute, with the basal jomt somewhat incrassate and considerably longer than the second ; 
second, third, and fourth joints becoming gradually shorter, fifth joint about as long as 
third and fourth together. 
Type of the genus: Bourdonnaisia mahensis, sp. nov. 
It is difficult to speak of the affinities of this genus. In several points it resembles 
Celostoma, but differs from that genus in its less convex form and general outline, in the 
absence of a sutural stria and the presence of a seriate arrangement in the punctuation on 
the elytra, &c. It appears to be isolated, and is very remarkable in its complete wing- 
lessness, and in the sexual dimorphism in the antennee of one of its species: I am unaware 
that any other case is known among the Hydrophilidz of the ¢ antenna having a different 
number of joints from that of the ?. 
Habitat. A long series of the two species was obtained, and the specimens were only 
found in extremely circumscribed areas on the very summits of the highest peaks of Mahé 
and Silhouette, at elevations of over 2000 feet, in the highest and dampest forest-zone. 
These peaks are covered with forest of the endemic “capucin” tree, Northea seychellarum, 
which has big smooth leathery leaves. These leaves, when fallen and dead, collect in 
hollows on the ground, lying closely on one another and (owing to the extreme humidity) 
having films of moisture between them. In this moisture the beetles live: when the 
leaves are pulled apart and turned over the little creatures are seen crawling on the wet 
and slimy surfaces, their shape causing them to fit closely down on to the leaf, and their 
somewhat depressed form being doubtless a convenience in the narrow spaces between the 
leaves. They were found nowhere but in this particular habitat, and are further remark- 
able in that one species is confined to Mahé and the other to Silhouette* (an arrangement 
which, together with the restriction of areas, recalls the distribution of many Hawaiian 
Coleoptera). 
The name Bourdonnaisia is taken from the Governor of Mauritius, Mahé de la 
Bourdonnais ; the largest island of the Seychelles was named “ Mahé” after him in 1744, 
and the whole group was for some time known as “Les Iles de la Bourdonnais t.” 
17. Bourdonnaisia mahensis, sp. nov. (Plate 14, fig. 12). 
é¢. Sat breviter ovalis, corpore supra nigro-piceo, subtus piceo-ferrugineo, palpis 
antennisque flavis, harum clavis nigrescentibus, tarsis flavo-ferrugineis; capite levi, ad 
marginem anteriorem rarius tenuissime punctulato; prothorace scutelloque levibus ; 
elytris marginibus externis postice parum explanatis, sat fortiter, crebre, et regulariter 
serlatim punctatis, punctis serierum alternatarum parum fortioribus. Long. corp. ca. 
132 mm. 
a, antennis 8-articulatis; 2, antennis 9-articulatis. 
* The finding of these beetles is referred to in the writer’s introductory paper, Trans. Linn. Soc. London, 
ser. 2, Zool., vol. xiv. 1910, pp. 25, 29, 33. 
t See J. Stanley Gardiner, in the Geographical Journal for February, 1907, p. 152. 
