For many years chemists and entomologists have been seeking the hypothetical ideal insecticide, namely, a material which is toxic to insects at an economical dosage, which is not injurious to the host plant or animal sprayed or dusted with it, and which does not leave on foodstuffs a residue that is poisonous to man or domestic animals. Certain organic compounds approach closer to this ideal than any products of mineral origin, and the successful use of these against same of our most injurious insects has greatly stimulated the testing of countless organic products for insecticidal value.

For some time I have doubted whether the existing determinations of certain of Walsingham's species of plumes, based on the revision of this family by Barnes and Lindsey, were correct. Through the kind offices of Messrs. Tams and Stringer of the British Museum of Natural History I have been furnished with drawings of the left claspers of the male genitalia of a number of Walsingham's types in the genus Oidaematophorus; a study of these drawings in connection with my own slide material has confirmed my suspicions and shown that in at least two cases there had been misidentifications by the above-mentioned authors. With a view to clarifying the situation somewhat in this extremely difficult group I offer the following notes.

A medium sized, polished black species, closely resembling picipes Aubé in general facies. Under side polished metallic black; legs dark, especially the middle and hind pairs.

This treatment of the Lauxaniidae occurring in a somewhat limited faunal area is offered as an introduction to a more extensive study of the group which I hope to undertake before very long. It is based on material in a number of private and institutional collections that have been available to me as well as on my own material collected during the last three summers at Abbotsford, Quebec. The list of species at the end of the paper includes all the available data on their distribution in Canada.

The material here described represents three new species and one new variety. These were received by the writer from J. K. Jacob of the University of British Columbia and from D. Denning of the University of Minnesota.

The following notes were made from a study of several species of Arctic Coollembola collected by Mr. W. J. Brown, of the Division of Entomology, Ottawa. Mr. Brown accompanied the voyage of the Canadian Arctic Patrol during August and September, 1935. During the trip he was able to collect on the southern shore of Baffin Island, and also well within the Arctic Circle as far north as Ellesmere Island.

The following observations and conciusions are based upon ephemerids from temperate North America and principally upon material from the eastern United States. It is perfectly conceivable that in other parts of the world, where the fauna and also the environmental conditions are different, the conclusions reached here may not be applicable.

In working over considerable Eupitheciid material collected a number of years ago by the late O. C. Poling in south-western Texas (Jeff Davis Co.,) I have come across several species which appear to be undescribed. I realize that there is always a certain amount of danger in determining as new any species in this genus until such time as the genital characters of all described species in both sexes have been definitely determined.

In the mass of literature, dealing with the fall webworm there are few references to the number of larval stadia. Bruner ( I ) states that there are four or five molts in eastern Nebraska. Dyar ( 2 ), who made measurements of the head capsules, found seven stadia. Snodgrass (3) found six larval stadia. He figures the first, second, fifth, and sixth instars.

It is strange that such a distinct genus as Aulacus should not have been recognized by American workers, but there seems to be no doubt that our Pammegischia Provancher, 1883 is merely Aulacus Jurine, 1807.

While collecting in the Cape Breton region of Nova Scotia early in July 1936, Dr. J. McDunnough and the writer collected a series of more than one hundred specimens of a P. scudderi form, commonly flying in a sphagnum bog about one and one half miles north of Baddeck on Highway No. 5, and which we thought might possibly be the race aster, described by Edwards from the Cape Race region in southern Newfoundland.

Male: Length of body (dried) 5 mm., of the forewings 1.8 mm., of the hindwings 1.5 mm. Color of body black, the abdomen with a mid-dorsal brown line; legs dark brown.