During the course of investigations dealing with the biological control of insect pests of conifers, several species of sawflies were found to be heavily attacked by the tachinid parasite Phorocera hamata A. & W. The present paper describes the immature stages and indudes the life-history of the parasite under laboratory conditions.

Agrilus anxius Gory has been reported as breeding in numerous species of birches and poplars. Because species of Agrilus are often poorly characterized morphologically, and usually restrict their feeding to one or to a few closely allied species of plants, it has been suspected that two species were confused. Barter, working in New Brunswick, noted that male specimens reared from, or artracted to, birches and poplars were separable allvays by characters of their genitalia. He found also the differences in biology which described below. Study of material in the Canadian National Collection and the U.S. National Museum shows that the genitalic characters hold in specimens associated with food-plants in other localities. Smith (1949, Nature 164: 237), working with material reared in New Brunswick, found that males and females from birches have 22 chromosomes, and those from poplars only 20. Thus it has been demonstrated that two species, one feeding on birches, the other on poplars, have been confused as Agrilus anxius.

The genera Nearctopsylla Rothschild 1915, Corypsylla Fox 1908, and Corypsylloides Hubbard 1940, all apparently strictly Nearctic, comprise a natural group which is intimately associated with certain mammals of the Order Insectivora. A subfamily, Nearctopsyllinae, of the Hystrichopsyllidae, has recently been proposed (Holland, 1949: 102) to accommodate these three genera, which are well separated from other fleas on the basis of a number of well marked morphological characteristics.

In the course of studies on the insects of rose hips Dr. W. V. Balduf, of the University of Illinois, reared and sent me for identification two species of Opius, both parasites of Rhagoletis alternata (Fall.). These are distinct from all described American species, and so far as I have been able to determine, they are different from all species of Opius known in Europe, where the host also occurs. Accordingty, both are described here as new.