INSECTA MADERENSIA. 97 



terminal) one of its labial palpi, will be more than sufficient to prevent the possi- 

 bility of confounding it, on closer examination, with Hydrobius. 



76. Hydrobius conglobatus, WoU. 



H. subglobosus nitidiusculus niger, minutissime punctulatus, prothoracis lateribus diluto-testaceis, 

 elytris confertissime et subtilissime granulatis, singulo stri^ suturali postica leviter impresso, ad 

 marginem anguste, sed ad apicem late testaceis, pedibus rufo-piceis. 



Long. corp. lin. 1-li. 



Habitat Maderam borealem excelsam sylvaticam, rarissime, — ad summam originem convallis Ribeiro 

 de Joao Delgada dictje d. 19 Jul. a.d. 1850 a meipso detectus. 



H. short, subglobose, black, and slightly shining; regularly punctured above with somewhat distant, 

 but excessively minute points. Prothorax with the sides broadly testaceous. Elytra with a 

 very lightly impressed sutural stria on each behind, but none whatsoever in front ; rather less 

 shining than the prothorax, and, in addition to the punctures (which are not disposed in strife), 

 most minutely and closely granulated (a sculpture, however, which is only apparent under a high 

 magnifying power) ; the lateral margins narrowly and obscurely, but the apex broadly, testaceous, 

 — the junction of the darker and lighter portions being usually somewhat abrupt and oblique, 

 (the suture also, when the elytra are upraised, appearing sUghtly pale). Wings entirely obsolete. 

 Palpi and antenna testaceous. Let/s rufo-piceous. 



A most distinct and interesting little Hydrohms; and one which, from its 

 minute size and subglobose body, bears a considerable prima facie resemblance (as 

 ah-eady stated) to the genus Chcetarthria. Its antennse and trophi however prove 

 it to be a true Hydrobius : and it would appear to be the Madehan representative 

 of the common S. globulus of more northern latitudes, — although abundantly 

 separated from that insect, specifically, in structure, sculptiu'e, and form. Thus, 

 to say nothing of its behig apterous, it is much shorter, more globose, and less 

 highly polished than the S. globulus ; the pale apex of its elytra, instead of 

 shading off gradually and imperceptibly into the darker base, is usually well- 

 defined and abrupt, terminating ol)liquely at about one-third of the distance from 

 the extremity ; and the large and deep punctiu-es which are so apparent on the 

 upper surface of that species are, in the S. conglobatus, far apart and excessively 

 small ; whUst the elytra are (in addition) most closely and finely granulated, — or, 

 more strictly perhaps (for it is only beneath a very high magnifying power that it 

 is perceptible), densely crowded Avith an under-series of most dehcate and minutely 

 impressed points. This peculiarity of sculpture indeed (although a microscopic 

 character) is exceedingly remarkable, and one which I do not see developed, to 

 the same extent, in any other member of the FMlliydrida with which I am 

 acquainted. From the S. globulus it likewise recedes in the club of its antennae, 

 which is large and perfoliated, and with the ultimate joint (instead of being 

 acuminated) exceedingly globose. It is, apparently, of the greatest rarity, and 



o 



