The work of my assistant, Mr. A. N. Gartrell, in southern British Columbia during the season of 1935 has resulted in considerable additions to our knowledge of the genus Ameletus in thisprovince; not only have the nymphs of A. oregonensis McD. and vernalis McD. been tied down, but two new species have been discovered.

It is proposed to deal with these in the present article but before doing SO it might be well to call attention to an error which has crept into Traver's key to the adults (1935, Biology of Mayflies, 447) ; in this key the first caption reads “Several cross-veins in forewing margined with brown, so that wing appears speckled” and under this heading is included as first species validus McD. This is incorrect as the wings of validus are not speckled but lightly and evenly suffused with brownish-amber, and the species, if properly keyed, would fall into caption 6, where it is distinguished from shepardi Trav. apparently by the darker-colored abdominal segments. Similior McD., as second species under caption I, is also wrongly keyed; in this species the wings are practically clear hyaline and the correct keying would lead to caption 13 (alticolus McD.) to which species it is allied but differs in genitalic characters.