18 Mr. T. V. Wollaston on the Coleoptera of St. Helena. 



tory motions, had then become sedentary, and lay moored to 

 a rocky surface, or was partially buried in its sandy matrix ; 

 in such a position its upper or more exposed surface consisted 

 of the posteal half of the area ; and this portion, either exposed 

 or discovered by the motion of the excurrent and incurrent 

 siphons, invariably became a prey to the marine flesh-eaters : 

 a portion more or less large is always found broken away and 

 removed. The whole general aspect of the adult valves ex- 

 hibits that worn or abraded condition with which Ave are also 

 familiar in Byssoarca, and doubtless resulted from similar 

 causes in both instances. 



I hope to present faithfully executed figures of this byssi- 

 ferous Trigonia in a Monograph on the British Trigonias, 

 now in preparation for the Palajontographical Society. 



IV. — On the Coleoptera of St. Helena. 

 By T. Vernon Wollaston, M.A., F.L.S. 



[Concluded from vol. iv. p. 417.] 



Fam. 19. Antliribidse. 



(Subfam. Ar^ocerides. 



Linea transversa prothoracica hasilaris^ marglnem ipsum ba- 



salem elevatum efficiens.) 



Genus 35. Ar^ocerus. 

 Schonherr, Cure. Disp. Meth. 40 [script. Araecerus] (1826). 



52. Ara>ocerus fasciculafus^. 



A. breviter ovalis, crassu.s, brunueo-piceus, pube brevi squamseformi 

 demissa cinerea griseaque vestitus necnon in elytris plus minus 

 obsoletissime (sc. in interstitiis alternis) longitudinaliter tessel- 

 latus ; capitc prothoraceque (subter pube) opacis, densissime et 

 rugose punctatis, illo in medio tenuiter carinulato oculis maximis 

 prominentibus, hoc subconico, postice late bisinuato, costa trans- 

 versa in marginem basalem coeunte necnon utrinque marginem 

 lateralem (usque ad medium lateris ductum) efiiciente, angulis 

 posticis subrectis ; elytris apice tniucato-rotundatis, (subter pube) 

 subopacis, densissime et rugose granulatis ac leviter crenulato- 

 striatis ; antennis pedibusque elongatis et (praecipue iUis) graci- 

 libus, illis rufo-testaceis clava obscuriore, his rufo-ferrugineis, 

 tarsorum art" 1"^° longissimo. 



Long. corp. lin. 2-2^. 



CurcuUo fascicvlatus, DeGeer, Ins. v. 276, t. 16. f. 2 (1775). 

 Anthribi(s coffee, Fab., Syst. Eleuth. ii. 411 (1801). 



Two examples of an Armocerus, which were taken at St. 

 Helena by Mr. Melliss, I feel almost confident are referable to 

 the A. fascicidatus (which is usually known in collections as 

 the coJf('(e of Fabricius), though I have thought it desirable to 



