Among plants that possess toxic properties few are so well known, or so much dreaded, in North America, as poison ivy (Rhus toxicodendron). The plant is distasteful to nearly all herbivorous animals, though its berries are eaten by a few rodents and birds. On the whole it is permitted to flourish unmolested and it has managed to enlist the cooperation of several birds as aids in the distribution of its seeds. The immunity enjoyed by this plant from larger creatures does not, however, apply to the smaller forms of life and among its insect enemies Coleoptera, Diptera and Lepidoptera are representd. A study of the lepidopterous insects found feeding upon poison ivy was begun some years ago and a number of species were reared. The notes relating to these have now been brought together under the above heading.

The writer has had by him for some years a sniall series consisting of both sexes of an interesting mosquito taken on one of the small coastal islands near Victoria, British Columbia. Description has been postponed from time to time in the hope that further specimens, together with larvae, would indicate the status of this species in relation to another form occurring commonly in the mountains, and interior and northern parts of the province. Since there seems little chance of these being secured at present it is thought best to offer a name and describe the species at this time.

The members of this genus are all small and globose and are easily separated from other Cercopidae, but here the easy part abruptly ends. The varieties are widely variable in size, form and color, ranging in most species from large pale forms through spotted, striped and variously ornamented ones on down through coppery and bronzy shades to small black forms at the other extreme. The representatives of this group are distributed through North and South America where some 68 or 70 different forms have been named. All of the earlier ones and most of those of later date have been founded on size and color markings alone, which vary with the sex, the food plant, the environment and in some cases at least with the season. Under the circumstances it is manifestly impossible to determine the number of species involved or to work out a stable nomenclature until extended collection and careful life history has been done in the areas involved.

The present paper is an attempt to review and bring up to date our knowledge of the Canadian species of net-winged Midges or Blephariceridae. Since the publication in 1903 of Kellogg's “Net-Winged Midges of North America,” several new species have been added to our list and additional records have come to hand thus increasing our knowledge of the distribution of several species; also certain generic changes seem advisable and it is hoped that the present paper will serve to facilitate the identification of our Canadian species.

In a pamphlet entitled “Burrowing Mayflies of Our Larger Lakes and Streams,” published in 1920 in the Bulletin United States Bureau of Fisheries, Vol. XXXVI, pp. 269-292, Professor Needham, discussing the species of the genus Hexagenia, makes the statement (op. cit. p. 279) that he is “unable to recognize more than two good and distinct species in the Eastern United States—a lowland species from lakes and rivers, Hexagenia bilineata Say. and an upland bog-stream species, H. recurvata Morg.” He amplifies this statement in previous paragraphs (p. 278) by applying the name bilineata Say. “to all the variants of the species that occupies the beds of our larger lakes and streams. The color differences appear to be only differences of degree. Even the differences of male genitalia—usually our ultimate criteria of species—are intergradient.”

The location selected for hibernation by this bark-beetle has long been a mystery and it was believed at first that, in common with other members of the Scolytidae, these beetles did not depart from the usual custom of hibernating in their tunnels in the bark where they had matured from the egg.