78 INSECTA MADERENSIA. 



greater portion of the surface. Antennae less infuscate than in the other states. (The extreme 

 pale variety of Porto Santo.) 

 Var. e. somewhat larger and broader than any of the above states ; brassy-green, and with a bluish 

 tinge unequally distributed over the surface ; the elytra almost immaculate, the fascia being 

 obsolete, and the patches only just indicated. Legs, especially the tibiae, more or less infuscated 

 in parts. (Ravines in the south of Madeira.) 



Throughout all the Madeii-an Coleoptera there is perhaps no insect which dis- 

 plays such an extraordinary range of colouring as the present one does ; and 

 although it is true that the section of Bembidhim to which it belongs is essentially 

 a A'ariable one, yet I am not acquainted "nith any Feryphns in which the paler 

 liatches of the elytra are so remarkal)ly unstable, or which appear to be so com- 

 pletely under the control of external circumstances, as are those of the B. Atlan- 

 ticum* : and indeed unless viewed in the mass, we should scarcely be inclined to 

 recognise the same species in the many diflferent aspects which it puts on between 

 its extremes. The examination however of a very large number of examples, and 

 a carefid consideration of the several localities and altitudes in which they were 

 taken, has convinced me that there is unquestionably but a single type of form 

 amongst my entire series, since the whole are so intimately connected, by success- 

 ive gradations both of outhne and colom% that it is perfectly impossible to isolate 

 even a single specimen, or to draw a line of specific demarcation between any two 

 consecutive members of the chain. It will be perceived, by a reference to the 

 above diagnosis, that the insect in question passes unperceptibly from nearly a 

 pure green, thi-ough a well-defined spotted state, into one which has the ehi;ra 

 abuost testaceous, — the paler portions being at last so largely developed as to 

 become confluent and almost to cover the entire sm-face. In Madeii"a proper the 

 darker varieties would seem to be tyjiical ; whereas in Porto Santo the brightly 

 coloured ones preponderate, and in fact are all but universal. Both extremes do 

 nevertheless occur in both islands, the tendency being merely, in either case, to 

 assmne the particular modification characteristic of the spot. In the north of 

 Madeira the specimens are somewhat narrower than either the southern or the 

 Porto Santan representatives. I have taken it abimdantly in tlie Eibeiro de Sao 

 Jorge, Avhere, on the 17th of May 1850, I observed it va literal profusion, near the 

 old road from Santa Anna to Ponta Delgada, AAhich crosses the valley at a greater 

 distance from the sea than the present one does, and consequently at a somewhat 

 higher elevation. In the south of the island it is far scarcer, — the tributary 

 ravuie to the Curral das Romcu-as being the only spot in which I have hitherto 

 detected it. In Porto Santo it is tolerably common : and, at edges of a small 

 stream which finds its way over the abrupt rocks of the northern shore, from the 



* Our present insect is jjrobably allied to (lie B. Ltmtanicum, Putzeys (Entoni. Zcit., a.d. 18-15, 

 p. 139) ; nevertheless I should state that I forwarded speeiiiicus to 51. Duval, of Paris, duinng the time 

 in which he was preparing liis monograph on the European Bemhidia, who pronoimced them to be un- 

 questionably new. 



