Among others, Schwerdtfeger, 1931, Gosswald, 1934, and Morris, 1949, have used frass-drop samples as indirect measurements of the density of forest insect populations with some success. The method has also been used to assess the effects of various insecticides on the feeding of treated larvae (Rhumbler, 1929; Schwerdtfeger, 1930) and to study the influence of weather upon the feeding and development of forest insects (Monro, 1935).

Mature larch sawfly drop to the ground and spin cocoons in the moss or duff. The ground snrface of tamarack bogs is usually uneven, and the moss is variable in moisture content. During hot dry weather the moss on the tops of hummocks in dry sites becomes dry, while that in the depressions remains moist. During periods of heavy rain, or in wet sites, the depressions may be filled with water, while the hummocks usually remain above the water.

MacGillivray (1952) listed aphids of the genus Aphis from the Maritime Provinces. Following are further records, from this region, of species of the tribes Aphini, including additional species of Aphis, Panaphini, and Lachnini. Slides of most of the material are at the Fredericton laboratory.

In a previous communication of this series (4), some general properties of the epicuticle of the two-striped grasshopper Melanoplus bivittatus were deduced from permeability measurements and chemical tests under various conditions. Among other things, it was found that the epicuticle is covered by a lipid layer, which regulates the rate of permeation of moisture through the cuticle. Because it has already been shown (2, 17, 21, 23, 24) that the rate of evaporation from the cuticle of several insects is a function of temperature and age, a study was undertaken of the effect of these factors upon the transpiration through the cuticle of grasshoppers in various instars.

Logging slash constitutes an environment supporting a particular association of insects and other arthropods. At first, the species in the community are governed by the character of the slash, but with the passage of time the condition of the slash changes, the rate of change being directly affected by bark beetles and other wood borers that facilitate entry of wood-destroying fungi. As the environment changes, those species for which the habitat is no longer suitable drop out, leaving in the association only those that can exist under the new conditions. Insect communities in slash, logs, and dying trees have been studied by Hopkins (1893, 1899), Clemens (1916), Blackman and Stage (1918, 1924), Graham (1925), DeLeon (1934), Beal and Massey (1945), Howden and Vogt (1951), and others. The succession of communities of animals inhabiting slash, logs, and dying and dead trees has been shown by Adams (1915) and Savely (1939) to continue until the wood has disintegrated completely.

This moth was first reported on this continent as a pest in a consignment of peanuts, received in California from China (de Ong, 1919). Mr. Hahn W. Capps, of the United States Department of Agriculture, informs me, in litt., that 6 adults from that infestation, together with 2 from “near prunes” in 1930, and 8 from a prune warehouse in 1931, at San José, are in the U.S. National Museum.

Nomada obscurella Fowler, 1902, was originally described from one male from Berkeley, California, March 18, from Ranunculus californicus, under the name N. obscura Fowler, 1899 (preoccupied). Nomada fowleri Cockerell, 1903, was described from a female from Corvallis, Oregon, April 15, 1897 (A. B. Cordley). In connection with a study of some interrelationships of some Ranunculus bees we have become convinced that the two are synonymous. Although in general we disapprove of the association of sexes by elimination, in this case we regard the circumstantial evidence so strong as to leave little doubt that they represent the two sexes of a strikingly sexually dimorphic species.

L'étude monographique de H. C. Fall (1922), “The North American species of Gyrinus”, a permis à de nombreux entomologistes de reconnaîrre assez facilement les Gyrins des territoires inventoriés par eux-mêmes et a facilité la mise en ordre des collections existantes. Nous en voyons la preuve dans les quelques additions ou listes qui parurent durant les dix années suivantes. Wallis (1926) décrit le Gyrinus dubius et le G. hatchi; il restaure le G. piceolus Blatchley qui avait été réduit au rang de synonyme par Fall. Chamberlain (1929) décrit le G. gehringi, provenant de l'état du New Hampshire. Brown (1928) donne une liste des espèces canadiennes. Il énumère vingt espèces pour la seule province de Québec, dont la plupart proviennent de la région de Hull ou de Covey Hill. Le Gyrinus opacus n'est cependant mentionné que pour la baie James. En 1931, Fall donne la description de Gyrinus instabilis dont le type et les paratypes proviennent de l'Alaska. Depuis, très peu de travaux semblent avoir été faits sur ce genre d'insectes, soit au Canada, soit aux Etats-Unis.

A study of 2,500 adults of the California five-spined engraver, Ips confusus (Lec.), has shown that the sex of this beetle can be determined from a secondary sex character with an accuracy exceeding 99 percent. Insects often have secondary characters that indicite sex, and in species with concealed genitalia, reliable secondary characters are especially useful for rapidly separating the males and females. Where such characters are lacking, a dependable determination of sex can only be made by the laborious procedure of dissection for a check of genitalia.

In working on the biology of Hoplitis producta (Cress.) and going through a large number of nests of that species, one nest was discovered which was quite distinct from the others. At first, it was thought that this nest was perhaps the nest of another species of Hoplitis; however, the subsequent rearing of the bees and their identification has shown the nest to belong to Heriades (Neotrypetes) variolosus variolosus (Cresson). This is the first record of the nesting habit of any member of the subgenus Neotrypetes, and while the record is far from complete, it seems that for sake of a more complete picture on the nesting habits of the Megachilidae that it be reported at the time. Rau (1) has recorded the emergence of two individuals of Heriades (Physostetha) carinata Cresson from a hollowed out stem of sumach, but gave no details on the nest construction.

This investigation was carried out to determine and explain some of the major factors underlying the variability in concentration of certain bark beetles in slash laid down under different cutting systems. Little is known on the life histories and natural control factors of many of the bark beetles inhabiting lodgepole pine (Pinus contorta Dougl. var latifolia Engelm.) and on the effect which different methods of logging have on the insects. Flash outbreaks in lodgepole pine stands frequently result from the breeding of certain bark beetles in slash remaining after logging operations. The opportunity to carry out this investigation was presented to the Calgary Laboratory in 1952, when the Federal Forest Service initiated studies on selectively cut lodgepole pine. This eventually became a co-operative project between the Federal Forest Service, Department of Northern Affairs and National Resources, and the Calgary Laboratories of Forest Zoology and Forest Pathology of the Division of Forest Biology.

Pineus pinifoliue (Fitch) was first described (6) in 1858 under the name Chermes pinifoliae. His description of the adult gallicola migrans on the needles of white pine contained characteristic phases of the form sufficient to distinguish it from other Adeiginae. Thomas (13), in 1879, described the characteristic cone-like gall on spruce and named the species forming the gall Chermes abieticolens. In 1906 Patch (12) observed the migration of the gallicola migrans from galls on black spruce, Picea mariana (Mill.) B.S.P., to the needies of white pine, Pinus strobus L., thus proving that Chermes abieticolens Thomas was a synonym of Chermes pinifoliae Fitch. She described the nymph and adult of the gallicola migrans and sexupara and included a drawing of the adult gallicola migrans. In 1928 Annand (I) revised the Adelginae and placed the species in the genus Pineus. He described and figured the fundatris, gallicola migrans, and exsulis.

It has now been well established that the cuticle of many insects is covered by a discrete layer of lipoidal material. Ramsay (26), Wigglesworth (32), Beament (4), and others have shown that the rate of evaporation-temperature curves from insects are characterized by breaks occuring at a “critical” temperature. In the previous paper of this seriis, Chefurka and Pepper (8) have shown that the rate of evaporation-temperature curves from Melanoplus bivittatus show a transition region from approximately 43 to 50°C.

Before the introduction of the parasite Mesoleius tenthredinis Morley into Canada in 1910, the larch sawfly had periodically caused devastating outbreaks that eventually resulted in the destruction of nearly all the mature larch east of the Rockies. The parasite at first gave control wherever it became established and, fallowing its release in Central Canada, the larch sawfly caused no serious damage there until 1938, when it again began to flare up, first in central Manitoba and then in Saskatchewan, Alberta, Ontario, Minnesota, and Wisconsin. Associated with the present resurgence is a loss of effectiveness on the part of M. tenthredinis and this appears to be related to the development of an immunity reaction on the part of the host (Muldrew, 1953a). The larch sawfly in British Columbia is, however, still highly susceptible to the parasite and, apparently, parasitism by N. tenthredinis keeps the level of abundance of the larch sawfly so low that at difficulty is experienced in obtaining host material for study purposes.

The application of lethal agents of any kind in entomological research is usually aimed at the determination of mortality as related to such factors as dosage, temperature, and time. Mortality is the yard-stick and survivors merely the fraction that did not die. After an arbitrarily selected interval the experimental material is categorized as dead or alive, with sometimes an intermediate group such as “subnormal” inserted. This third class is often essential, for its members do not properly qualify as dead or alive, terms that imply totality. It is also a nuisance, for several reasons: (1) it blends gradually into the other two categories so that classification itself is subject to errors of judgment; (2) its numerical uncertainty affects the other categories not only at the time of initial classification but also later by the death or total recovery of some of its members; (3) as long as any treatment-effect persists, the situation remains quantitatively incomplete.

The common North American ant-lion, Myrneleon immaculatus DeGeer, is generally distributed throughout the United States and has extended its range northward into Canada at various places. Throughout its range, the regular, cone-like pits of larvae of this species inay be found in dry, sandy stretches that in an ecological sense constitute small, isolated desert regions.

Temperature is one of the most important of rhe physical factors with which desert species must contend. It is the purpose of this paper to present the results of gn investigation of the effects of temperature upon the behaviour and activity of larvae of M. immaculatus in their natural habitat.

This description is based on an examination of 25 larvae of Hylobius radicis Buch. recovered from the damaged root-collars of dead and dying Scots pine, Pinus sylvestris L., in the vicinity of Angus, Ontario. Since larvae of at least one species of the genus Pissodes (P. approximatus Hopk.) may be found in the same trees, I am also taking this opportunity to compare the external structures of the larva of H. rardicis with those of the genus Pissodes (see Böving, 1929; Anderson, 1947). Where possible, and particularly in the description of the head capsule and mouth parts, the terminology used is that of Anderson.

In studies of sawflies, the family Pamphiliidae has been much neglected especially from the morphological stand point. Yuasa (1922) made a study of the larvae, but the genus Cephalcia was dealt with rather briefly. Ross (1937) and Benson (1945) made comparative morphological studies of the adults and showed the phylogenetic position of the family. More recently, Middlekauff (1953) published a description of Cephalcia marginata, a pine web-spinning sawfly which was the subject of the present study.

The red clover thrips, Haplothrips niger (Osb.), was first recorded from the state of Iowa and described by Osborn in 1883 under the name Phloeothrips nigra. The species hns since been collected and observed in many parts of the United States, southern Canada, and Europe. It wils reported in New England and recognized as a potential pest of red clover by Muggeridge (1933). Minute and very active, the adult insect is glossy black in contrast to the nymphal stages, which are bright red. In Minnesota, common host plants are alsike clover, Trifolium hybridum L., and red clover, T. pratense L.