66 



DYTISCID^E. 



similar to those of more northern latitudes ; but I do not believe 

 that they can be regarded as specifically distinct from the latter. 



198. Hydroporus Clarkii. 



Hydroporus Clarkii, Woll., Ann. Nat. Hist. ix. 438 [June] (1862). 



Andalusia, Clark, Journ. of Ent. i. 469 [Sept.] (1862). 



Clarkii, Woll., Cat. Can. Col. 77 (1864). 



Habitat Canarienses (Fuert.), in rivulis vulgatissimus. 



Abundant in all the streams of Fuerteventura, of the Canarian 

 Group, though it has not yet been observed in any of the other islands. 

 We may, however, expect it to exist in at any rate Lanzarote. It is 

 very closely allied to the H. affinis, from Sardinia ; but I am assured, 

 nevertheless, by Schaum that he believes it to be truly distinct from 



that species. 



199. Hydroporus Ceresyi. 



Hydroporus Ceresyi, Aube, Hydrocanth. 543 (1838). 



Lyellii, Woll, Cat. Mad. Col. 26 (1857). 



Ceresyi, Id., Cat. Can. Col. 78 (1864). 



Habitat Maderenses (P to S to ) et Canarienses (Lanz.), in aquis salinis 

 subsalinisque interdum stagnantibus sed plerumque fluentibus, 

 rarior. 



The H. Ceresyi of southern Europe I have taken sparingly in Porto 

 Santo of the Madeiran Group and in Lanzarote of the Canaries, where 

 it seems to occur for the most part in waters which are more or less 

 brackish. In the former I met with it towards the northern side 

 of the island, beyond the little village of Camacha, and in the latter 

 in the saline lake of Januvio adjoining the south-western coast. 



Judging from the few individuals which I have seen from Porto 

 Santo it would appear to be (on the average) a trifle smaller and 

 darker in that island than is usually the case elsewhere, and conse- 

 quently in my Madeiran Catalogue I described the Porto- Santan ex- 

 amples under the title of //. Lyellii ; but I now believe that that 

 particular form ought not to be treated as more than a slight and 

 unimportant insular variety, and I have therefore suppressed it as a 

 species. Nevertheless if future material should prove it to be really 

 distinct (which I cannot but consider most unlikely), the trivial name 

 of Lyellii will in that case have to remain for it as hitherto. 



200. Hydroporus vigilans. 



Hydroporus vigilans, Woll, Ins. Mad. 86 (1854). 

 , Id,, Cat. Mad. Col 25 (1857). 



Habitat Maderenses (Mad.), in aquis fluentibus vulgaris. 





