1897.] 11 



S. humeralis and S. flavescens put in an appearance by promiscuous sweeping, as also 

 did Phytobius quadrituberculatus. Nanophyes lythri was abundant upon Lythrum, 

 and Oymnetron noctis in the flowers of Linaria vulgaris, but we failed to find the 

 rare O. linaricB, which Mr. C. Gr. Barrett took in the allotments here in 1871.* In 

 one field at Town Street we found two of Mr. J. J. Walker's capturesf— J5arw 

 abrotani, common at roots of Reseda lutea, and Ceiithorrhynchus asperifoliarum, 

 one only, at those of Echium vulgare, together with C. geographicus, in some 

 numbers. In all we noted just over three hundred species of Coleoptera between 

 September 16th and 26th, but could nowhere find the " Brandon Sandhills," the 

 nearest being at least two and half miles out of the town — at Wangford. 



Everton House, Berners Street, 



Ipswich : November, 1896. 



WATER-BEETLES FROM THE ISLAND OP TONG^ATABU. 

 BT J. J. WALKER, R.N., F.L.S. 



A few weeks ago my friend Dr. V. Gunson Thorpe, R.N.jF.R.M.S., 

 Surgeon of my old ship, the " Penguin," during her second surveying 

 commission, kindly gave me a little tube containing some water-beetles 

 of two species, which he had taken in the island of Tongatabu (lat, 

 21° 5' S., long. 175° W.). This locality appearing to me to be of more 

 than ordinary interest, I submitted the insects to Dr. Sharp, who has 

 kindly determined the larger one as a form of Hydaticus Goryi, Aube, 

 the other being our well-known Bhantus pulverosics, Steph. This 

 latter species is of enormously wide distribution, its already known 

 range (cf. Sharp, Monogr. Dytiscidae, Trans. Royal Dublin Soc, vol. ii, 

 ser. 2, p. 609) extending from the South of England eastward through 

 Central and Southern Europe, North Africa, Mesopotamia, China, 

 Japan, and Java to Australia, New Caledonia, and New Zealand ; a 

 closely allied species, R. annectens, Sharp, having been described from 

 Samoa. It is, to say the least, somewhat startling to receive a British 

 water-beetle from an island on the opposite side of the globe, almost 

 in the centre of the tropical Pacific Ocean. Hydaticus Goryi is 

 recorded from Australia, New Caledonia, and Malasia. Dr. Thorpe 

 informs me that Tongatabu is a low island composed of upraised coral, 

 entirely destitute of streams or ponds, the only source of fresh water 

 being the rain, caught in tanks or pits, cut in the solid coral rocks by 

 the natives, and it was in these "catch-pits" that the beetles were 

 taken. They had communicated to the alcohol in which they were 

 preserved a pleasant scent, somewhat resembling that of orange-peel, 

 a scent I have noticed in some Chinese species of Hydaticus, but not 

 in any of our British DytiscidcB, so far as my experience goes. 



23, Ranelagh Road, Sheerness : 

 December 5th, 1896. 



* cf. Ent. Animal, 1872, p. 42. f cf. Ent. Mo. Mag., xxii, pp. 86, 87. 



