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III. On the Classification of the Natural Tribe of Insects Noxo- 

 NEC TIDES, with Descriptions of the British Species. Bij Wil- 

 liam Elford Leach, M.D. F.R.S. and L.S. 



Read April 4-, 1815. 



Before laying down the characters of this interesting and natu- 

 ral tribe of insects, it may not be deemed improper to give a very 

 short account of what has been done by preceding entomologists. 



Linn6 and all his predecessors comprehended the species under 

 the generic appellation Notonecta. The accurate Geoffroy was 

 the first who separated Notonecta into two genera, which have 

 been adopted by most succeeding writers, excepting Linne, who 

 in the last edition of his Systema Naturte has merely given the 

 synonyms of that author, without taking the least notice of the 

 important characters which induced him to separate them. 



De Geer confounded the animals of this tribe with Nepa and 

 Naucoris, whilst Latreille and Olivier placed them in a division of 

 their family Hydrocorisce. 



In the Edinburgh Encyclopedia I separated them from the 

 Hydrocorisce, and placed them in a particular tribe, named in 

 that work Notonectides, which term I shall adopt in the following 

 little essay. 



Ordo. 



