412 Rev. H. Clark on the Dytiscidae 



examples a faint line-like longitudinal marking is apparent on each 

 elytron : legs and antenna fusco-flavous. 



H. Blalceii may be separated from other species of this section by- 

 its concolorous elytra. 



3. Breviter ovati : thorax angxjlis posticis cum elytris 

 angulum ortusum s-spe formans. 



11. H. collaris, Hope (Proc. Ent. Soc. Lond. 1841, p. 48). 



I do not know this species, which is not in the British Museum 

 or any London collection : according to Mr. Hope's brief diagnosis it 

 is piceous in colour throughout, and very finely punctate : in length 

 it is If, in breadth f line. 



In the Catalogue of Hydrocantharidae of the British Museum 

 (1847), the name under which this species was described by Mr. 

 Hope is sunk as a synonym, and in its stead is proposed the specific 

 name of " thoracicns " : this alteration was proposed probably from 

 the fact that there was already a Eygrotus collaris (D. collaris of 

 Panzer), and that Hygrotus had been merged as a subdivision of the 

 genus Hydroporus. But D. collaris of Panz. is nothing more than H. 

 reticulahts of Fab. and other writers ; it is itself merely a synonym 

 (see Brit. Mus. Cat. p. 31) ; and thus the name is at the service of any 

 subsequent writer who may select it, wherewith to designate any 

 other species of the genus. This accidental oversight is the more 

 unfortunate because since the date of this catalogue Boheman has 

 described an African Hydroporus (Ins. CafFr. i. 1848) under this 

 same name of collaris, which must now (by reason of the restoration 

 of Hope's original name to this Australian species) be changed for 

 some other name. 



The species was found near Port Essington. 



Professor Westwood has been so good as to examine for me the 

 original typical example of this species, which is in the Oxford Uni- 

 versity Museum : by his description of it, as well as by a drawing 

 which he has very kindly made of the insect, it is apparent that H. 

 collaris must be referred to this subsection. Mr. Westwood notices 

 four abbreviated striae-like lines on the elytra, very faintly impressed, 

 extending from the base a little beyond the middle. No notice of 

 these striae is found in Mr. Hope's concise description. 



12. H. undecim-maculatns, n. sp. 

 H. ovatus, latus, subdepressus, crebre punctatus, niger vei fusco-niger, 



rufo-fusco maculatus. 

 Long. corp. vix If lin., lat. vix | lin. 



