In June 1932 a very immature nymph of Ephoron leukon Will was found in the Credit R. near Erindale, Ontario. In 1934 full grown nymphs of this same species were found in great numbers in the same locality after their hiding place was once located. They are burrowing nymphs which inhabit a tubular burrow associated with stones in the rapids. Loose stones. when turned over revealed no nymphs and lackcd the marks of the tubes on them. Stones, however, which were partly imbedded in fine grey silt (originating from the breakdown of shales in the vicinity) when turned over- revealed nymphs clinging on the sides and bottom in the remnants of the tubes. Curiously enough the time of day at which col1ecting was done was important.

In the preparation of the following notes, I have become indebted to Professor E. H. Strickland and Mr. C. A. Frost for the loan of specimens and to Mr. P. J. Darlington Jr., and the Museum of Comparative Zoology for the loan of much material and for permission to study the aedeagus of the type specimen of carbo Lec. Mr. K. G. Blair, by comparisons with types, has nlade it possible for me to identify semimetallicus Walk. and aeripennis Kby.

Male. Antennae weakly bipectinate. or more properly speaking lamellate and fasciculate, the width of each lamella being noticeably less than in the closely allied pulla Grt. Palpi and head clothed with rough blackish hairs ; tegulae crested,the basal portion deep smoky, the upper half light grayish tipped with darker, a fine blackish transverse line at the point of denemarcation of the two colors; patagia clothed with mixed gray and blackish hairs ; thoracic vestiture deep smoky with a small blackish median tuft on metanotum.