MIGRATION AND DISPERSAL OF INSECTS 1 "cOLEOPTERA. 319 



remained almost entirely at the surface. Walker states {loc. cit., p. 

 15) that the only Cyhhter rocselii he ever saw alive was taken about an 

 hour before sunset one very warm evening in August, 1876, when 

 waiting on the pier at Besika Bay ; the beetle, a fine ^ , was on the 

 wing and flew deliberately into the sea, close enough to the pier to be 

 caught by hand ; there was no freshwater stream within a mile of the spot. 

 He further notes that at Kavala, Turkey, a large living specimen of 

 Hydrophilus piceus was caught in the sea at a "seining party," actually 

 in the the net among the fish. The distribution of certain aquatic 

 coleoptera is, indeed, very remarkable, but perhaps one of the most 

 marvellous instances of wide distribution among our water beetles is 

 that of Uhantus pidverosus, which extends from the south of England, 

 eastward through central and southern Europe, North Africa, 

 Mesopotamia, China, Japan, and Java to Australia, New Caledonia, 

 New Zealand and Tongatabu, in the centre of the tropical part of the 

 Pacific Ocean. 



As bearing only indirectly on the question of dispersal, Lewis 

 records {Ent. Mo. .!/«//., xviii., pp. 138-139, 213) some very interesting 

 observations made in July, 1880, whilst ascending a volcano in South 

 Yezo. Whilst sitting on the ridge of the crater he noticed a most 

 refreshing mountain draught ascending the sides of the mountain. 

 He also observed a number of KlatenJae and a few Silpliidae dead and 

 dying, lying on the sand around him, and watched those that arrived 

 fresh and vigorous from the forest below, drop on the ridge, and, in 

 three hours, join the army of dead that was there. The conclusion at 

 which he arrived was that the beetles were carried up by the air- 

 currents, involuntarily, from the forest below, and that life was 

 destroyed by the abstraction of the fluids of the body, due to the 

 great heat of the sand forming the ridge around the crater. His 

 further suggestions as to why, of all the many species in the forest, 

 the Klatcridae and Silphidae alone are carried up to perish on the dry, 

 heated lava, are exceedingly interesting, but so far outside the question 

 that we are discussing that we can only say that he considers it due to the 

 fact that the elytra of these groups, when raised to the angle necessary to 

 allow the membranous wings to be put into action for flight, are just in 

 that position to catch the full force of the upward current, and that 

 these species with ample elytra meet their death by being mechanically 

 lifted up into the arid region of sand. No Elaters were found in the 

 crater, as, at the ridge, the direction of the air-current changed and 

 they fell to the earth. The interesting general remarks and the light 

 which these observations throw on the shortened wing-cases of certain 

 coleoptera, e^j., Braclichjtra, &c., must be here omitted. Nor are the 

 observations of Bruce and Thornley [Ann. Scutthh Nat. Hist., 1895, 

 pp. 28-37), on a collection of coleoptera made by the former on tbe 

 summit of Ben Nevis, without considerable interest. The latter 

 gentleman was requisitioned by entomological friends to collect such 

 insects as he might meet with at the summit, and, accordingly, daring 

 May and June, 1895, he captured a large number on that part of the 

 mountain which is above 4350ft. in altitude, the Ordnance Cairn, at 

 4406ft., marking the extreme elevation ; the ground from which the 

 insects were obtained consisted of an elongated plateau more than one- 

 third of a mile in length, and averaging about 70 yards in width ; 

 altogether it is nearly eleven acres in extent. Bruce says that the 



