ta Not?* r Vict - ^ at 



xxxv. 



this particular species is unknown to him, and is probably new. 

 There being no lack of specimens, I collected a tubeful, some 

 of which are in the National Museum collection. To gain 

 an idea of their excessive abundance, the cubic contents of 

 one patch (out of three or four within a length of ten yards 

 of gutter) worked out at one million and twenty-five thousand 

 individuals. The morning was dull, but after the sun came 

 out for a few hours there was a marked stampede of the little 

 insects, probably to the bases of the grass tufts, from whence 

 they seem to have been washed, the expanse of grass being only 

 a few inches above the level of the gutter. This particular form 

 is shaped like an elongated wood-louse, with three pairs of 

 thoracic legs, six body segments, a pair of short, unequally- 

 segmented antennae, and two short, stout appendages near 

 the hinder extremity, used for jumping. No sucking disc was 

 visible on the under side of the body. The feet are terminated 

 by a sharp, curved claw. The last abdominal segment carries 

 either a pair of elongate, triangular cerci surrounded by long, 

 curved bristles, or a pair of sharp, backward-curving claws. 

 Scattered bristles are seen covering the general surface of the 

 body and appendages, and these seem to serve in an efficient 

 way to entrap air so that in flood waters the insects float 

 calmly on the surface buoyed up by a silvery film. To a palae- 

 ontologist this little creature is of especial interest, as it shows 

 many features of an archaic type, which, so to speak, haw 

 been borrowed from more than one extinct group of arthropods. 

 Such are the terminal joints of the antennae, which end in pad- 

 like structures suggestive of the swimming paddles of the 

 sixth pair of feet in the extinct water-scorpions, Eurypterus, 

 and probably used for the same purpose. The specimens 

 somewhat resemble Lipura ambttlans, Linn., but differ in having 

 a tapering rather than broadly-rounded extremity to the 

 abdomen. Lubbock, however, states that in the family 

 Lipuridae there is no saltatory appendage and the body is 

 cylindrical, so that it is probable that the present form repre- 

 sents an entirely new group of family rank. Mr. F. G. A. 

 Barnard has drawn my attention to the determination of one 

 of our Collembolas by Lubbock (now Lord Avebury) from 

 specimens sent to him by the late Mr. H. Watts {Vict. Nat., 

 vol. hi., 1887, p. 135) as a Degeeria, but the present form is not 

 of that genus, which lias a cylindrical body, club-shaped hairs, 

 long saltatory appendages, and fairly long antennae. — F. 

 Chapman, Balwyn. 



Erratum. — In vol. xxxiw, page 123, line 14, for Thrasymene 

 read Trachymene. 



