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(G. subsłriałus s. str.), puncturcs of clytral striac dcep at the sidcs, much less decp, often subdelete, towards the sulure; upper surface black with a brilliant aenescence, duli specimens not uncommon, beneath black with the mesosternum and last abdominal segment, typically, of a elear red, sometimes infus-cated, rarely (var. fowleri O.-C.) black, epipleurs yellow, red, or, rarely, infuscated; median lobe of aedeagus narrow, rather long, apex transversely truncated.

Gyrinus subsłriałus is the commonest of the European Gyrinidae, being both abundant and widely distributed. It is a very variable species and considerable differences in size, colour and shape are not infreąuently to be found amongst the individuals swimming together in the same school. The commonest aberration is the duli black form. This was called var. B by SHARP and this method of designating it may well be ad-hered to. OcHS in 1927 redescribed the G. corpulenłus of SCHATZMAYER, 1903 and named it var. schałzmayri, the name corpulenłus being preoecupied. It is a very duli yariety which SHARP appears to have included under var. B although I am by no means conviced that he had seen the typical var. schatz-mayri. The true var. B is a black aberration of the typical G. subsłriałus and occurs singly. The thorax and elytra are smooth without puncturation, and often with long scratches. The var. schałzmayri is a very different insect in many ways; the surface of the pronotum and elytra in typical examples is crenulated and covered with an easily visible fine puncturation. This yariety, when it occurs may be present in some numbers. Whether the yariation is genetic or due to physiological effects of the environtnent, I do not know, but there can be little doubt that it is different in its origin from ab. B.

The var. fowleri which I described in 1930 is a smooth insect, very black on the dorsal surface and having the mesosternum and last abdominal segment black. There is little or no fine puncturation and the punctures of the elytral striae are subdelete towards the suture. The size is usually rather large.

The var. siculus Regimbart first described from Sicily but common in many parts of Europę, is distinguished by possess-ing a fine puncturation on the pronotum and on the elytra. The yariety is also characterised by being slightly morę elongated