A recent development in microscopy certain to be of great interest to entomologists is the Scanning Electron Microscope. This machine overcomes the difficulties of studying solid surfaces with a standard light microscope and the problems of the extremely small limits of penetration of the electron microscope. This new microscope focuses a stream of electrons into a beam as small as 1 μ in diameter which moves over the surface of the specimen in a regular pattern, causing secondary radiations to emerge from the surface of the specimen. These are collected by a very sensitive detector and converted to an image similar to that produced by a television tube.

The New World species of the staphylinid subfamily Micropeplinae are revised. Three genera are recognized: Kalissus Leconte with 1 species, Micropeplus Latreille with 11 species, and Peplomicrus Bernhauer with 3 species. Of the three previously recognized subgenera of Micropeplus, Arrhenopeplus Koch is placed in synonymy with Micropeplus, and Peplomicrus is elevated to generic status. New species are: M. durangoensis from Mexico, M. neotomae from California and Oregon, M. browni from eastern Canada and the United States, M. robustus from California and Oregon, M. lecontei from southern California, and P. dybasi from Costa Rica and Panama. Micropeplus obliquus Leconte is placed in synonymy with M. sculptus Leconte, and M. oregonensis Hatch is placed in synonymy with M. punctatus Leconte. The genus Micropeplus is divided into six species groups based on an examination of both Old and New World species. A checklist of the species of Micropeplinae places all the described species in the proposed classification. Two African species, M. africanus Cameron and M. carayoni Jarrige, and one Central American species, M. acumen Sharp, are transferred to the genus Peplomicrus.

This paper contains notes affecting the classification of the Bruchidae of United States and Canada, a list of all species found north of Mexico, and a list of World genera and their type-species. The Mexican Merobruchus vacillator (Sharp) is added to the fauna of this area. Transferred from our list to that of Latin America are: Acanthoscelides californicus (Boheman), Megacerus eugenie new name for Bruchus ramicornis Boheman nee Erichson, and Mimosestes innotatus (Pic.). The following are synonymized: Spermophagus (Zabrotes) semicinctus Horn (1894) with Zabrotes subfasciatus (Boheman 1833); Bruchus subserripes Fall (1910) with Acanthoscelides compressicornis (Schaeffer 1907); Lithraeus electus Bridwell (1952) with Lithraeus elegans (Blanchard 1851); Bruchus alboguttatus Motschoulsky (1874) with Meibomeus musculus (Say 1831); Bruchus bivulneratus Horn (1873) with Bruchus abbreviatus, inadvertently validated by Say = Sennius abbreviatus (Say 1824); Bruchus nigrinus Horn (1873), B. nictitans Motschoulsky (1874), and B. depressus Fall (1912) with Sennius cruentatus (Horn 1873); Bruchus pythonicus Pic (1913) with Stator pygidialis (Schaeffer 1907); and Bruchus biguttatus Fabricius (1801) = Bruchus biguttellus Schoenherr (1833) with Callosobruchus chinensis (Linnaeus 1758). Original spellings of the specific names of two species are revived: Megacerus pygidalis (Motschoulsky) nee pygidialis Pic, and Megacerus discoidus (Say) nec discoideus: authors. Bruchus lividus J. E. LeConte 1824 is placed in our list as an unrecognized species. Thirty-five new combinations are proposed.

The Mexican and Central American species of the Genus Isomira Mulsant (Coleoptera: Alleculidae) are revised. Ten species and four subspecies are treated, of which six species and all the subspecies are described as new. New species are: Isomira championi, I. howdeni, I. rotundata, I. mexicanus, I. acuta, and I. alticola. New subspecies are: Isomira howdeni hidalgoensis, I. subaenea soror, I. s. punctata, and I. s. guatemalensis. A key is presented for the determination of the taxa.

Chermes lariciatus was described by Patch from the gallicola migrans and further information on this form was given by Annand under the genus Adelges. The complete polymorphic cycle on spruce and larch is described here, with information about the life history, habits, seasonal development, and morphology. Fundatrices overwinter as nymphs below new buds of spruce on 1-year-old needle bases. Gallicolae develop in early summer within galls which are globular in shape and usually only partly surround the twigs. Sistentes overwinter as first-instar nymphs on larch buds, wedged among the bases of the needles or scales, with the heads up and the mouth parts inserted into the bud. The progredientes and sexuparae move to the new cones in early summer when there is a cone crop, but settle on the leaf buds when there is none. Sexuales nymphs on spruce remain under the parent sexuparae during development. A diagrammatic representation of the seasonal development and a description of the morphology of the first-instar nymph and adult of each form is given. A discussion concerning the validity of this and related species is included.

In New Jersey, Typhlodromus pomi (Parrott) was the only predacious phytoseiid mite on most non-sprayed apple and deciduous trees. It also became the most numerous phytoseiid mite recolonizing apple trees a year after toxic spray residues had dissipated. Amblyseius fallacis (Garman) was the first phytoseiid mite collected from apple trees following cessation of toxic sprays and was usually abundant at the time of large red mite populations; later, an influx of several different species occurred. A. fallacis was the most common phytoseiid mite on low growing plants and was able to tolerate higher residues of toxic materials than other species. Other phytoseiids taken from sprayed apple trees in order of abundance included A. driggeri n. sp., A. amicus (Chant), T. longipilus Nesbitt, T. conspicuus (Garman), T. mexicanus (Garman), T. caudiglans Schuster, and A. pepperi sp. n. Species other than T. pomi found on non-sprayed apple trees were A. finlandicus (Oudemans), T. longipilus, T. caudiglans, and T. conspicuus. None of these species was entirely confined to apple. Five other species were collected that were not found on apple: T. flumenis Chant, T. pyri Scheuten, A. elongatus (Garman), A. okanagensis (Chant), and A. picketti sp. n. Three species collected from greenhouse plants in association with tetranychid mites were: A. fallacis, T. longipilus, and A. picketti.

Three new species of Amblyseius are described. Two undescribed males and the spermathecae of the females are illustrated.

Tuberculatus Mordwilko as here understood consists of the following 14 species: californicus (Baker), capitatus (Essig and Kuwana), columbiae Richards, kiowanicus (Hottes), maureri (Swain), orientalis new species, pallidus (Davidson), pasaniae (Davidson), querceus (Kaltenbach), quercicolus (Matsumura), querciformosanus (Takahashi), stigmatus (Matsumura), tuberculatus new species, and yokoyamai (Takahashi). Tuberculatus previously included querceus and columbiae. Each species is redescribed and illustrated, and a key and a host index are provided.

This brief concerns the present state of knowledge of the immature stages of Lepidoptera. It is written with three objects in mindéto focus attention on the widespread neglect of serious studies of the immature stages and the weaknesses to be found in projects involving them, to interest in this rugged, highly demanding branch of lepidopterology the few students that may be qualified, and to urge the provision of appropriate positions for which the students can apply.

The distribution, ecology, and host-plants of the European skipper, Thymelicus lineola (Ochs.), are described, and notes given on its biology and abundance in continental Europe. Agricultural practices are responsible for its virtual absence from hay-fields; however, even in undisturbed wild host-plant communities, it is never abundant, and has never required control measures as in Canada. Parasites of T. lineola are listed, with notes on their life-histories, distribution, host spectra, relative abundance, annual fluctuations, and interpopulation variations. Parasites reared were Phryxe vulgaris Fall., Thecocarcelia incedens Rond, (both attacking larvae, but sometimes emerging after host pupation), Rogas tristis Wesm. (larval parasite), Labrorychus delarvatus Grav. (larval–pupal parasite), Stenichneumon scutellator Grav. and Brachymeria intermedia Nees (pupal parasites); an undetermined mermithid was reared from larvae and also once from an adult S. scutellator. Rogas tristis was attacked by the hyperparasite Mesochorus macrurus Thoms., and S. scutellator by Gelis cursitans F. Potentialities of the more important species for biological control of T. lineola in Canada are discussed. S. scutellator, which is well synchronized with the host, regularly parasitizes 30–50% of pupae and is the most promising natural enemy for introduction, although in Canada it will compete with the native Itoplectis conquisitor (Say). R. tristis (3–57% parasitism) and P. vulgaris (8–44%), with high constancy in Europe, might be considered for introduction to Canada because of the absence there of effective native larval parasites. T. incedens, although probably a specific hesperiid parasite, is uncommon (usually 1–5% parasitism) and has low constancy in central Europe. All other species encountered are rare on T. lineola. Comparison of parasite complexes in Europe and Canada, where the host has acquired 22 natural enemies, shows that four genera are represented in both areas; of three holarctic species two have been found associated with T. lineola only in Canada, and one only in Europe.

Nine new species of Slaterocoris Wagner are described from North America: pilosus from British Columbia; alpinus from Colorado; apache from Arizona, Colorado, and Utah; flavipes, solidaginis, and sparsus from California; argenteus, grandis, and simplex from Durango, Mexico. The other species in the genus are: ambrosiae (Kngt.), atratus (Uhl.), atritibialis (Kngt.), breviatus (Kngt.), croceipes (Uhl.), hirtus (Kngt.), longipennis Kngt., mohri (Kngt.), pallidicornis (Kngt.), pallipes (Kngt.). robustus (Uhl.), rubrofemoratus Kngt., sheridani Kngt., stygicus (Say), and utahensis Kngt. Strongylocoris uniformis Van D. is placed in synonymy with Stiphrosoma robusta Uhl. Strongylocoris albibasis Knight does not belong to Slaterocoris and will be dealt with in a subsequent paper. All species are keyed and the male genitalia illustrated.

Larvae of the larch sawfly, Pristiphora erichsonii (Htg.), were fed foliage of tamarack, Larix laricina (Du Roi) K. Koch, treated with solutions of the vital dyes, Nile blue sulphate, rhodamine B, and coriphosphine O, to determine their suitability as markers. Coriphosphine O was highly toxic at the concentrations administered but successful tagging was obtained with the other two dyes. Optimal dye retention and survival were obtained when larvae were fed for 3 days early in the last stadium using Nile blue sulphate and throughout the last stadium using rhodamine B.

Both dyes persisted throughout development and were incorporated in the cocoons and the oviposited eggs. They could be readily seen in all stages except for the cocoons and for eggs that contained rhodamine B. The dyes could be detected in cocoons by treating them with cold KOH followed by ethanol. The presence of rhodamine B in the eggs could be ascertained by its yellow fluorescence in ultraviolet.

The dyes incorporated in the cocoons are relatively stable and laboratory tests indicate they probably can withstand weathering under normal field conditions over a 1-year period.

The use of these dyes for internal marking should prove useful in studying adult dispersal and flight range and as a technique for use in population studies of the larch sawfly.

Attractive frass was produced by female D. pseudotsugae within 2 hours after boring into fresh Douglas-fir logs and peak attraction was reached in 8 hours. Production declined after 2 weeks but increased again if the females were allowed to attack new logs. Frass was collected, stored at −40°C, and extracted in benzene. The extract was distilled and chromatographed on a silica gel column. An olfactometer was developed in which beetles walking toward a light, passed into a narrow air stream. If the air stream contained attractive substances, beetles oriented upwind. Males showed a weak positive response to female frass extract and distillate over a wide range of low stimulus intensities and an abrupt increase at higher intensities. Over 20% of the test beetles responded to concentrations of 5.1 × 10−4 and 2.3 × 10−3 g-equiv of extract and distillate respectively, while stimulus intensities 100 times greater evoked responses over 80%. The silica gel fraction that eluted in the volume between 350 and 400 ml contained a highly attractive component.

In a 5-year study at Beaverlodge, Alta. (lat. 55° N.), 1-kg packages of honey bees hived in mid-April (10–23 April) produced more honey than those hived in early May (5–13 May) in only 2 years. The major nectar flows ranged from 22 June to 22 August.

The rate of brood rearing as determined by egg-laying of queens and the build-up as shown by adult bee populations at various periods after hiving increased progressively with delay in hiving dates which ranged from 4 April to 3 May, and were attributed to the more favorable climate of the later hivings. Adult bees in excess of 1 kg per package did not increase egg-laying of queens or the build-up of colonies.

Restriction of daylength by 6 hours per day for 8–9 weeks had no effect on colony brood rearing or build-up. Restriction of daylength to 6.5 hours per day for 7 weeks caused a small initial reduction in egg-laying in the first brood cycle (1.5 weeks after hiving) but no differences were noted later, either in egg-laying at 4.5 weeks or adult populations at 9.5 weeks. When colonies were in complete darkness for 3 weeks, egg-laying was reduced 35 to 60%.

Methods are presented for sampling and constructing life tables for Scolytus ventralis LeConte with the objective of comparing the histories of populations inhabiting individual trees. A bark area of 72 sq. in. was an effective sample unit. Within-tree variation was minimized by taking two sample units from two vertical strata at each sampling date. Trees were serially sampled several times during development of the insect.

Population tables were constructed for each sampling date and life tables were developed from the complete series of population tables. The precision of the life table estimates varied between 10% and 40% of the mean and generally decreased as population density diminished during development. A sampling design is presented for increasing the precision of life tables, and methods are given for determining the number of trees required for estimating the mean density when studying populations occupying large areas.

The innervation of a pregenital, the genital, and postgenital segments of the male and female of Schistocerca gregaria (Forskäl) is described in detail and is compared with other orders of the Insecta.

Three new species of the westermanni group of the genus Euxoa are described: Euxoa cryptica occurs in the southern Sierra Nevada and White Mountains of California, Euxoa juliae occurs in the central Sierra Nevada, and Euxoa austrina is evidently confined to the San Gabriel Mountains of southern California.

A new genus, Melastola, with type-species Gymnonychus resinicolor Marlatt, and two new species, Pristola clarki and Melastola ferruginosa, are described. Keys to the genera and known species of the tribe Pristolini are presented. New distribution records for Pristola macnabi Ross are reported in North America.