5169915525

21

from Wigry wcrc vcry dark underneath, the mesostcrnum and lasl ahdominal segment being almost or quite black and the epipleurs much infuscatcd. 1 have seen other dark specimens but nonę so dark as these.

Gyrinus natator Linn. 1758

Average size:    ^ł — 5,20 x 2,90 mm; _r — 5,90 x 3,25 mm,

Largest;    5,55 x 3,10 mm;    6,25 x 3,30 mm,

Smallest:    5,00 x 2,70 mm;    5,50 x 3,05 mm,

L o c a 1 i t i e s: — Near Wigry, Pond Nr, 2, V, 1931, 1

5

Pond

Nr, 3, V, 1931, 1

Pond Nr, 4, V, 1931, 1

Pond Nr, 2, VI. 1931, 4

4

Pond Nr, 3, VI,1931, 7

1

Pond Nr, 4, VL1931, 9

6

t

Pond

Nr, 6, VI,1931, 1 V; Swarzewo p, Puck, 22, VIII, 1922, 1 ci Sobolewo p. Suwałki, 19, IX, 1922, 4 _Struszta p, Brasław, 14,VIII.1924, 1 damaged speci-men; Okmianica p. Brasław, 15. VIII. 1924, 1

C\ 2    . ; Białowieża,

Świteź p. Nowogródek, 18.

VIII. 1924, 1

Hwozna, 10

W r

26—29. VIII, 1924, rezerwat, 7 i 8

nv.

9 _; , Łętowmia p, Nisko, 1 l^r, 3

Moderately convex; apex of elytra roundly truncated; pro-notum and elytra rarely with a well marked fine puncturation usually with the fine puncturation subdelete; punctures of ely-tral striae uniformly impressed; upper surface black, shining or duli, never brightly aenescent, under surface black, mesoster-num and last abdominal segment almost or quite black, epipleurs deeply infuscated; front, middle and hind tarsal claws red or yellow; median lobe of aedeagus rather short, moderately narrow, apex truncated transversely.

This species, the first of the Genus to be described, has been confused with G. substriatus Steph. until OCHS, 1927,

i 0    __ ^    _

(Uber die Gyriniden von LiNNE und FABRICIUS. Ent. Rundschau. Bd, 13, Nr. 1, pp. 34—42) pointed out that the Linnean

species differed in several respects from the species usually

described as G. natator L. In 1931 Messrs Britten and Day sent me 7 cf ⁷¹ and 3 Q 'y of a smali Gyrinus collected in Eng-land which I determined as G. natator L. and described in a paper „On Gyrinus natator L. and G. substriatus Steph.” (Ent. Mo. Mag. Vol. LXVII, pp. 195—198). The specimens received

from Poland confirm me in the conviction that the tw^ro species should be considered distinct. The materiał, upon which the measurements givcn above were madę, was all collected by Dr.