334 THE CANADIAN ENTOMOLOGIST. 



body is stated to be elongate. Now, no species of the genus or genera 

 variously known as Atoniya. Spinola ; Appnsus, Amyot and Serville ; 

 Cydodema, Dufour : Nervinops, Dufour ; Sphcerodema, Auctt., and 

 Diplonychus, Amyot and Serville, of those that I have seen (and my 

 collection contains nearly all the known species which at one time or 

 another have been ranged in these genera), is elongate. All are more or 

 less ovate. This view was enunciated by Leon Dufour in his " Essai 

 Monographique sur les Bel )stomide'=,'"^ who then said under Hy d racy r ins. 

 Spin. (p. 385): 'On a peut etre nial intcrprcie le genre Diplonychus iox\i\€ 

 en 1832, par M. de Laporte. Get autcur dit positivcment que les 

 Diplonychus ont le faciei dts Bclostoma ; que leur corps est elongatum, 

 que les tarses anterieurs se tcrminent par deu.x ongles elongati. Je le 

 deraande aux esprits serieux, ces traits sont-ils applicables aux Diplony- 

 chtn des auteurs de IVpf que ? Quant a moi qui ai etudie a fond cette 

 question, j'ai I'mtime conviction que le Diplonychus de M. de Lnporte a 

 du etre primilivement, fonde sur un grand Biiostome, analogue a mon 

 Algei iense."' 



Prof. Montandon has discussed the synonymy of this genus in one of 

 his able essays on Water-bugs,^ and his conclusion is that Diplonychus, 

 Lap., being unidentifiable, it is better dropped for the defined Sphcerodejna, 

 Lap., although he suggests that Laporte may have had before him a nymphal 

 Belostomatid (which is two-clawed) or a species of Hydrocyrius. Li his 

 discussion, however, it is evident that he is unfamiliar with Laporte's later 

 note cited above, in whicli he removes Belostoma rustica, Fab., from the 

 subgenus, and states that it is a Sphcerodema. While it is true and proven 

 that nymphal Belostomatids are two-clawed, none of those known to me 

 have the so-called " filets abdominaux " or " caudal setje." These are 

 characteristic of the adult only, and are not sexual characters, but rather 

 pertain to the respiratory apparatus, and are parts of the highly specialized 

 and modified sixth abdominal segment. I am familiar with all but one of 

 the described Belostomatid genera, and know about fifiy species, but of 

 these the only ones that have the " fiicies des Belostomes," and are at the 

 same time two-clawed, are the two species of Hydrocyrius I possess. 



6. 1863, Ann. Soc. Ent.. Fr. (4), 111. 



7. =columbiae, Spin. (Hydrocyrius). 



8. 1900. Notes s. qqs. jicnres de la Fam. Belostomidre — Bull. Soc. Sci, Buc. 

 An. IX, No. 2 and 3, pp. i to 8 (of separate). 



