296 ON THE EXISTENCE OF 



Sp. 9. Hyd. minutissima. Piceo-hrunnea: cajnte nigro, lato, 

 2)ostice dense, antice vix punctato ; oculis prominulis : 

 thorace lateribus rotundatls, antice latissbno, dense punc- 

 tato, ad angulos depresso: ehjlris elongatis, obtuse ad 

 apicem rotundatis, distincte punctato-strialis : pedibus, 

 antennis palpisque rufo-testaceis. (Long. corp. | lin.) 



Hydraena minutissima. Stephens. 



This species may be known from all the foregoing by its 

 minute size and the proportionately large head and thorax. 



I have taken one specimen of this species in the neighbour- 

 hood of London, but forget the exact locality. Newcastle- 

 upon-Tyne ; C. Hewitson, Esq. 



Sp. 10. Hyd. gracilis. Nigra, nitida : capite inter ociilos 

 punctato: thorace longiore, lateribus dilatatis, 2^unctato, 

 sulcis duobus longitudinalibus impresso : elytris nigro- 

 pticeis aut nigris, angustatis, jjunctato-striatis, sutura 

 paulld elevata ; antennis, palpisque rufo-piceis : pedibus 

 nigris, geniculis tarsisque rufis, (Long. corp. \\. lin.) 



Hydraena gracilis. Midler. Germar. Ins. Sjje. p. 94. 

 elongata. Curtis. 



Closely allied to H. riparia, but may be distinguished by 

 its more elongate narrow form, and black legs ; the eyes are 

 also rather more prominent. 



I have one specimen of this insect, but do not recollect its 

 locality. 



Art. XXXIIL — On the Existence of ^^ Natural Genera.''^ 

 By Alexander William Griesbach, Esq. B.A. of Trinity 

 College, Cambridffe. 



" Ne mea dona, tibi studio disposta fideli, 

 Intellecta prius quam sint, contemta relinquas." 



Of all the qualities of the human mind, there is none more 

 enviable, and none which has been the cause of greater good 

 to mankind generally, than an acute perception of the beauty 



