106 Dr. Sharp's Bevision of the 



vix angustato; elytris thorace tertia parte longioribus; 

 abdomine supra toto confertissime subtilissimeque punc- 

 tate. Long'. 1 lin, 



Mas; abdomine segmento 7° ventrali paululum pro- 

 ducto apice rotundato. 



Fern.; segmento 7° ventrali apice rotundato. 



H. longula, Heer, Faun. Col. Helv. 334. Hydrosmecta 

 longula, Th. Sk. Col. iii. 13. 



Size and form of H. fragilis. Antennae pitchy^ slender, 

 not thickened towards the apex, each joint longer than 

 broad, joint two longer than three, four shorter than 

 three, five to ten differing but little in length, eleventh 

 rather longer than the tenth. Head a little narrower 

 than the thorax; nearly square, not narrowed in front j 

 thickly and very finely punctured, with a more or less 

 obsolete impression on the middle. Thorax a little nar- 

 rower than the elytra, its length about equal to its breadth, 

 scarcely narrowed behind ; with a not very distinct long- 

 itudinal channel ; closely and very finely punctured. The 

 elytra are fully one third longer than the thorax, and are 

 also very densely and very finely punctured. The whole 

 of the upper surface of the abdomen is very densely and 

 finely punctured. 



The male is not easy to distinguish from the female, 

 the only difference being that the ventral plate of the 

 seventh segment of the abdomen is a little narrowed, and 

 more produced than in the female. 



Rare. I have found it on the banks of a tributary of 

 the Nith, near Dumfries, and also on the banks of the 

 Bowmont at Yetholm ; a few specimens were also formerly 

 taken by Mr. Wollaston at Slapton Ley. 



This species is very like H. fragilis, but is easily dis- 

 tinguished by its much more densely and finely punctured 

 abdomen, and its darker colour. 



Ohs. — This species accords sufficiently well with Heer's 

 description of H. longula. Kraatz's thinohioides is gen- 

 erally supposed to be synonymous with H. longula, Heer, 

 but I cannot find that Kraatz's description agrees accu- 

 rately with my specimens ; moreover two examples of 

 H. thinohioides sent by Ki^aatz to the British Museum, 

 are specifically distinct from the present species. Mr. 

 WoUaston's H. thinohioides from Madeira, is also a dif- 

 ferent species from the present one, having its head nar- 



