AQUATIC HETEROPTERA. 



75 



and H. alluaudi, except the armature of the middle trochanters. B. White 

 {loc. cit., p. 45), writes : " [the middle] trochanter armed with spines," but 

 these " spines " are not real spines, but stout setae, which are sometimes torn 

 off even during the life of the insect. I have also examined the type material 

 of H. alluaudi Bergroth in the Museum National d'Histoire Naturelle, Paris, and 

 am now quite sure that this supposed species is identical with H. princeps B. 

 White. Halobates matsumumi Esaki is also synonymous with this species. 



H. princeps is now known to be \videly distributed over the Indian and 

 Pacific Oceans, as far as the Seychelles in the west, and the Pacific coast of 

 Southern Japan in the north. 



GELASTOCORIDAE. 



7. Peltopterus macrothorax (Montrouzier). 



Galgulus macrothorax Montrouzier, Ann. Sc. Phys. Nat., Lyon, (2), vii, pt. 1, p. 110, 1855. 

 Scylaecus macrothorax Stal, Ofv. Vet.-Akad. Forh., xviii, p. 201, 1861 ; Enum. Hemip, v {SvensJc. 



Vet.-Akad. Handl, xi, no. 4), p. 139, 1876. 

 Peltopterus macrothorax Stal, Berlin, Ent. Zeit., vii, p. 408, 1863 ; Ofv. Vet.-Akad. Forh., xxvii, 



p. 706, 1870 ; Montandon, Bui. Soc. Sci. Bucuresci, viii, p. 779, 1899. 



Tutuila : Leone Road, a single 8-5 mm. in length, 9.ix.l926 (Judd). 



This species was previously known to occur in Woodlark L, Fiji, the 

 Philippine Is., N. Borneo, Aru, the Solomon Is., and Marianne or Ladrone Is. 

 In the British Museum collection there are, in addition to those from Woodlark I., 

 Fiji, the Marianne and Philippine Is., specimens from Ke Dulan (in the Ke [= Kei] 

 Islands, 1 1 9, 25.ix.1874, " Challenger " collection), Formosa (1 without 

 further data), and " Madgico-sima, Corea " * (3 $$). 



* These specimens from " Corea " were collected by Artliur Adams during the voyage of 

 H.M.S. Samarang under Captain Sir E. Belcher, C.B., R.N., and deposited in the British Museum 

 in 1845 with many other specimens. The three specimens are labelled " Corea," and only one 

 of them has a second label, " Dry sand, Madgico-sima." There is no doubt that these three were 

 collected at the same time. I believe that " Madgico-sima " is not an island near Corea, because 

 at the time of this voyage no Japanese name was officially used for the Corean geographical places 

 (" sima " or shima means " island " in Japanese). On the other hand, the Yayeyama Islands in 

 the Loo Choo Group, lying between Okinawa and Formosa, have sometimes been called as " Majico- 

 sima " or " Mayico-sima." It may be fairly safe to assume that this " Madgico-sima " is identical 

 with " Mayico-sima." If my assumption is correct, it is very interesting to find this typical 

 oceanic species on these islands (the chief islands are Ishigaki-jima and Iriomote-jima), which 

 are, together with Kotosho (= Botol Tobago), zoogeographically much more closely related to 

 the Philippine Islands than to Formosa, in spite of their closer proximity to the latter than to the 



