In view of the economic importance of blackflies as bloodsucking insects affecting animals and man, and the growing recognition of their actual and potential role as vectors of disease, it has been considered of interest to record the following notes concerning certain of their natural enemies, some of which may prove to be of value in developing biological control measures. These observations were made at various times over a period of several years, in connection with a study of blackflies carried out chiefly in the Ottawa district, the results of which have been published elsewhere.

Ludius divaricatus (Corymbites) was described in 1853 by LeConte. The sexes were described as different species, the female being named Corymbites crassus. Blanchard in 1889 pointed out that crassus was the female of this species. The writer has examined cast skins of larvae from which both males and females developed and found no characteristic difference between them. The genus Ludius contains a large number of species, but only a few larvae have been described or illustrated.

In a recent note (1938, Canadian Entomologist, LXX, 128) I suggested that this name should be applied in a strict sense to the species the larva of which feeds on Aster and Grindelia, but hesitated to separate the Balsamorrhiza feeder as a distinct species owing to lack of material; I had, however, called attention (1936, Canadian Entomologist, LXVIII, 63) to certain differences in the setal structure of the pupal cases which warranted further investigation.

My original intention was to describe a new species of the genus Enargia, but upon doing the genitalia of the “common widespread species”, I found that there were in reality two species and not one; Mr. F. H. Wolley Dod came to this same conclusion from a superficial examination of his material in 1905 (Can. Ent., xxxvii, (241-246) and further substantiated his conclusions in 1913 (Can. Ent., xlv, 130).

In the early part of August, 1938, Professor Caesar, Provincial Entomologist, received from Kenneth C. Hume of Ayton, Ontario, a letter containing insects said to be numerous in that district. Professor Caesar identified these insects as the European earwig, Forficula auricularia L. This identification was later confirmed by the Dominion Entomologist from specimens forwarded by Professor Caesar when he reported the outbreak. This is the first recorded outbreak of the species in Canada east of the Rockies.

Observations on the life histories of Polites verna Edw., Hesperia leonardus Harr., and Ancyloxypha numitor Fabr. are reported here. Previous work on the rare P. verna included a vague description by Scudder of a drawing of the egg and a full account of the last larval instar. Concerning H. leonardus only the egg and first instar were known. A drawing of the second instar was also described (Scudder, 1889). In a previous communication (Dethier, 1938) it was pointed out that the third brood of A. nomitor probably passed the winter in the larval stage. This is confirmed and further details presented.