228 [October, 



in lat. 9° 35' S., long. 119° 56' W., a position fully 1100 miles from 

 the nearest land, the north-eastern outliers of the Paumotu or Low 

 Archipelago, and more than twice as far from the coast of South 

 America. These oceanic specimens, which I have unfortunately lost, 

 were probably the widely distributed H. Wullerstorffi, Frauenf., 

 already known from the Western Pacific Ocean. Only a very few, 

 mostly young larvae, were taken in the tow-net, the adults appearing 

 to be well able to avoid the net in its passage through the water. In 

 all the harbours and open roadsteads of the Marquesas Islands, a 

 species which I refer with some reserve to B.. sohrinus, White, was 

 plentiful, especially in Omoa or Bon Eepos Bay, Fatou-hiva Island ; 

 and I saw what was probably the same species at Papiete, within the 

 barrier-reef which encircles the Island of Tahiti. S. Willlerstorffi 

 was also found at the Marquesas, but much less commonly than the 

 other. Rough weather prevented me from making further observa- 

 tions during this cruise, and in our numerous trips along the coast of 

 Chile and Peru, I never saw^ the insect at all ; these southern waters, 

 constantly cooled to below 60° F. by the Antarctic current, to a 

 latitude far within the tropic of Capricorn, are much too cold for the 

 continuance of the species, which evidently require a high temperature 

 during part of the year, at least. 



In the voyage of the " Penguin," I first saw Halohates in the Eed 

 Sea (lat. 20° 32' N., long. 38° 1' E.), but I had no opportunity of 

 taking more than one or two specimens until we arrived at Perim 

 Island, in the straits of Bab-el-Mandeb. Here a species, which is 

 certainly not the H. Sayanus, White, recorded from Aden, but agrees 

 well with H. proavus, White, from Gilolo, was found rather commonly 

 on the sandy beaches of the Island, under seaweed and other tidal 

 refuse, usually defunct, but often quite fresh and lively. I have a 

 note of seeing Halobates (sp. incog.) in the Indian Ocean about 900 

 miles E.S.E. of Sokotra. in lat. 8° 50' N., long. 71° 24' E , but have no 

 further record until our arrival in the Araf ura Sea, off the north- 

 western coast of Australia. A fine species, which appears to be 

 identical with S. regalis, Carpenter (described from Torres Straits 

 specimens), was by no means rare in the open sea, and in the channels 

 among the numerous small Islands. It was also frequently found on 

 the surface of pools of salt water left by the receding tide on the 

 coral reefs. On one of these (Guichen Reef, near Troughton Island, 

 lat. 14° 45' S., long. 125° 10' E.), I found, besides the Halohates, several 

 specimens of a species of the singular allied genus, Hermatohates, 

 Carpenter, closely related to, though differing in many respects from. 



