HYDROPHILID.E. 79 



235. Hydrobius marchantiaB. 

 Hydrobius Marchantise, Woll, Cat. Mad. Col. 31 (1857). 



Habitat Maderenses (Mad.}, ad rapes aquosas inter plantas humidas 

 Marchantice polymorpTice, L., praecipue in locis inferioribus parce 

 degens. 



Apparently peculiar to Madeira proper, where it may be regarded 

 as the representative in that island of the Canarian H. hcemorrhous. 

 I have observed it hitherto only in wet places along the north coast, 

 principally at low elevations, where it resides amongst the dripping 

 masses of Marchantia polymorpha which mat the rocks at the edges 

 of the waterfalls and trickling streams. 



236. Hydrobius conglobatus. 



Hydrobius congoblatus, Woll., Ins. Mad. 97 (1854). 

 , Id., Cat. Mad. Col. 32 (1857). 



Habitat Maderenses (Mad.), ad rupes et caet. in aquosis editioribus 

 rarissimus. 



Likewise peculiar (so far as observed hitherto) to Madeira proper, 

 where it occurs very sparingly about wet rocks and trickling streams 

 at a high elevation on the upper limits of the sylvan districts*. 



Genus 67. CHJETARTHRIA. 

 (Waterhouse) Steph., III. Brit. Ent. v. 401 (1832). 



237. Chaetarthria similis. 

 Clitarthria similis, Woll, Cat. Can. Col. 93 (1864). 



Habitat Canarienses (Can., Ten., Gom., Palma), hinc inde in aquosis 

 et humidis baud infrequens. 



This may possibly be a geographical modification peculiar to the 

 Canarian archipelago of the common European O. seminulum ; never- 

 theless it has a few small distinctions of its own, alluded to in my 

 diagnosis. It is not very abundant, but occurs in moist places and 

 about trickling streams in Grand Canary, Tenerrffe, Gomera, and 

 Palma. 



* The H. conglobatus differs from the marchantia, mainly, in its smaller size 

 and more finely punctulated surface (at any rate of the head and prothorax), and 

 in its elytra (which are a trifle obtuser, and less cariniform, behind) having their 

 sutural stria a little finer but nevertheless continued rather further towards the 

 middle (from the apex). 



