THE CANADIAN ENTOMOLOGIST. 335 



My friend Kirkaldy, in his recently-published list of genera," rejects 

 Montandon's work and adopts Diplonychtis, Lap., as the true generic 

 appellation of the Sphcerodema-Appasus-lSfervinops-Cyclodema-Atomya 

 series, but in consideration of the facts I have here set forth, the correct 

 synonymy, which may be intercalated in Kirkaldy's generic list, p. 151, is 

 as follows : 



Genus 5. — Sphcerodema, Laporte, 1832, Essai Hem., 18 (type fig. in 

 Fieber, etc.). The rest of the synonymy as in 



Kirkaldy, 1. c Type aufiulata, Fabr. 



Genus 7. — Diplotiychus, Laporte, 1S32, Essai, p. 18. 



= Hydrocyrhis, Spinola, 1850, etc. (The remainder of the 

 synonymy as in Kirkaldy, 1. c, p. 152.) 



IL 

 What is the true systematic position o{ Diplonychus, Lap. { — Hydro- 

 cyrius, Spinola) ? Kirkaldy in his work cited places Hydrocyrms, Spin, 

 (recte Diplonychiis, Lap.), between Linuiogeioti, Mayr, and Nectocoris, 

 Mayr, this genus being placed last in the family. Going further back, 

 Mayr^" places it between Benacus, Stai, and L i ?ntioget n, }>idiyr, and so 

 does Stai." Dufour,'^ however, seems to have been the only one of the 

 older entomologists to have had the true conception of the affinities of 

 Diplonychiis, Laporte ( = Hydrocyrius, Spinola). He places it between 

 Belosloma, A.\xci\.., WQC Ij-Mr. {= Amorgitis, Siai), and Zaitha, Am. & S. 

 { = Beiostojua, Latreille). Agreeing with Dufour, I believe the linear 

 relationship of the Belostomatid genera is more nearly expressed by the 

 following order : 



1. Benacus, Stai. 



2. AmorgiKs, Stai. 



3. Diplonychiis (Laporte), Bueno. 



4. Belostoma, Latreille. 



5. Abedtis, Mayr. 



6. Limnogeton, Mayr. 



7. Nectocoris, Mayr. 



8. Sphcerodejna, Laporte. 



9. 1906, List of the Genera of the Pagiopodous Hemiptera, etc., Tr. Am. Ent. 

 Soc, XXXII, No. 2, pp. 117 to 156 and r56a. 



10. 1871, Die Belostomiden, Verb. Zool. bot. Geo. Wien., XXI. 



11. 1865, Hem. Afr., III. 



12. 1863, Ess. Men. s. 1. Belost., Ann. Soc. Ent. Fr. (A.) III. 



