This is the first of a danned series of pauers on the taxonomy of the cocoons and puparia, cast larval skins, and other remains of parasitic Hymenoptera and Diptera that are found in or near the remains of parasitized hosts after the parasites have emerged. The study is based. at least initially, on the host species so that the keys and descriptions may be of use to those who work on the host species as such and who wish to name parasite remains they encounter. The parasites of Diprionidae will be dealt with first, because of the economic significance of these sawflies. The present paper deals with the known Canadian parasites of the European pine sawfly, Neodiprion sertifer (Geoff.), and includes descriptions of the structures that are of taxonomic significance and of the methods used in their study; these descriptions will be in general applicable to the species to be discussed in subsequent papers.

The adults, mummies, and final-instar larvae of the eight hymenopterous parasites of the pea aphid, Acyrthosiphon pisum (Harris), in Eastern Canada are described and illustrated. The history, synonymy, and biology of each species, and the problems of species differentiation in two of the genera, Aphidius and Praon, are discussed. Keys are given to separate the adults, mummies, and cast skins of the last larval instar.

Cocoons of Neodiprion sertifer (Geoff.) were collected in southwestern Ontario in 1941, 1943, 1946, 1947, and 1949 for experimental investigations at the Belleville laboratory. A total of 8,326 cocoons were collected, mainly within about eight miles northeast and east of Sarnia, Ont., but a few were collected at Strathroy and Brigden, Ont. Each cocoon was incubated separately in a small vial so that each parasite could be associated with the host cocoon from which it emerged. Sawflies emerged from 68 per cent of the cocoons and parasices from 12 per cent; dissection of the remaining cocoons showed 16 per cent contained dead sawfly larvae and pupae, and four per cent dead parasite larvae.

Il est sugg6r6 que la tribu Trioxini (Aphidiinae) devrait 6tre une sous-famille s6pa-r6e et appelde Trioxinae i cause de la pr6sence d'une protub6rance de I'hypostome qui ne fut pas trouv6e chez les autres aphidiid6s examin6s. A I'int6rieur de cette nouvelle sous-famille sugg6r6e, le genre Lipolexis semble €tre la forme la plus primitive exa-min6e parce qu'en plus d'avoir une protubdrance de I'hypostome, il a un 6pistome complet qui fait d6faut i tous les autres aphidiid6s examin6s. I1 est sugg6r6 que ce genre soit plac6 dans une tribu s6par6e nomm6e Lipolexini. Les trioxin6s semblent 6tre le groupe le plus primitif des Aphidiidae et forment un pont enire les Braconidae et les Aphidiidae. MEMOIRS OF THE ENTOMOLOGICAL SOCIETY OF CANADA NO. I52Les Aphidiini (Aphidiinae) semblent 6tre au sommet de l'6chelle 6volutive des Aphidiidae i cause de la perte ou r6duction de la scl6rite pleurosto-hypostomale, rendant les identit6s des pleurostomes et des hypostomes plus difficile.'-

INTRODUCTIONThis is the second in a series of papers on the taxonomy of the cocoons and puparia, cast larval skins, and other iremains of parasitic Hymenoptera and Diptera that are found in or near the remains of parasitized hosts after the parasites have emerged. The structures of tz~onomic sipificance in the separation of the species were described and discussed in a previous paper (Finlayson, 1960). The present paper deals with the known Canadian parasites of the European spruce sawfly, Diprion hercyniae (Htg.). Parasites of D. hcrcyniae that were dealt with in the previous paper are not described or illustrated here.