An earlier report on summit ant swarms (Chapman, 1954b) presented data and observations based on first-hand studies and results from 256 questionnaires returned, in 1952, from observers at mountain-top fire lookout stations in the western U.S.A. (Fig. 1). In 1953, questionnaires were again sent to fire lookout observers, including some in western Canada, together with specimen boxes for samples from summit ant swarms. A total of 318 of these forms were returned, of which 235 were accompanied by samples of ants. This is a final report on the material supplied by lookout observers, together with a few additional comments on the phenomenon.

This paper introduces new names and synonymies to North American workers and corrects a few errors in the literature involving North American species of Scolytidae. A few distributional records are included to support some of the proposed synonymies. For convenience of reference the names of the species involved are arranged alphabetically.

Neoleucopis pinicola Mall. is a common predator on the pine bark aphid, Pineus strobi (Htg.) in New Brunswick. The host adelgid occurs throughout most of the United States and southern Canada on white pine, Pinus strobus, L., Scots pine, Pinus sylvestris L., and Austrian pine, Pinus nigra Arnold (Craighead, 1950). It is also an occasional predator on the balsam woolly aphid, Adelges piceae (Ratz.) (Brown and Clark, 1956b). No reference to N. pinicola was found in the literature other than Malloch's (1921) description.

The balsam woolly aphid, Adelges piceae (Ratz.), causes serious damage to balsam fir, Abies balsamea (L.) Mill., in Eastern Canada. It was introduced from Europe before 1900 (Balch, 1952) and has also become established in the northeastern United States. In continental Europe A. piceae is common on Abies alba Mill. but is not so serious a pest as in Canada. It has an extensive complex of insect predators in both Canada (Balch, 1934) and Europe (Delucchi, 1954). Balch (1934, 1952) found those in Canada inadequate as control agents. Some of the predators of Pineus pini Koch and Pineus strobi (Htg.) studied by Wilson (1938) in England, and recommended for introduction to new areas, were imported to Canada and released against A. piceae. Predators were first introdnced from Ensland in 1933 and later from continental Europe beginning in 1951.

The Ischnoceran genus Mulcticola Clay and Meinertzhagen, 1938, contains five forms found on the avian family Caprimulgidae. The known species, and type host, are: M. hypoleucus (Denny), 1842, found on Caprimulgus europaeus europaeus Linnaeus; M. macrocephalus (Kellogg), 1896, found on Chordeiles minor henryi Cassin; M. nacunda nacunda Carriker, 1945, found on Podager nacunda minor Cory; M. nacunda peruviana Carriker, 1945, type host is unknown (presumed to be a member of the Caprimulgidae); and M. tenuiceps Carriker, 1945, found on Podager nacunda nacunda (Vieillot). A new species is described from material collected by one of the authors while assigmed to the United States Operations Mission to Thailand. The other new species is described from material in the British Museum (Natural History), which was graciously loaned by Dr. Theresa Clay. Appreciation is also expressed to the United Staces National Museum and to the Snow Entomological Museum of Kansas University for the loan of specimens.

Before the advent of synthetic organic insecticides, it was much more difficult to control the codling moth, Carpocapsa pomonella (L.), in arid, hot areas with a long growing season, as in the Pacific northwest, than in cooler areas such as Ontario, where there is more rainfall and usually a shorter growing season. As a rule, in all apple growing areas, the codling moth is most numerous during summers in which the temperatures are above normal, particularly if the prevailing temperatures are high at dusk, when the moth is ovipositing. Consequently, unsatisfactory control in hot, dry areas, such as the South Okanagan of British Columbia, was attributed largely to the direct and favorable influence of climate on codling moth development (Webster, 1936).

In 1913 Horace Gunthorp described a new Kansan lithobiid, Lithobius kansensis (4, p. 166), which he compared with what he took to be a closely related species, cantabrigensis Meinert (5, p. 177). Although the new species was inadequately characterized, it is still possible to say that it is undoubtedly referrable to Tidabius, a group proposed by R. V. Chamberlin in November of the same year (2, p. 80).

The signs of an Empusa muscae Cohn infection in dead flies were described over two centuries ago by de Geer (Kirby and Spence, 1826), who, however, attributed the cause to some factor other than a microorganism. Though the validity of the name Empusa has often been questioned, it is used in this paper following the suggestion by MacLeod (1956).

The following account deals with the transmission of E. muscae to species of Diptera under controlled laboratory conditions.