Each posterior spiracle is generally divided into three main parts—posterior spiracular plate, fell and spiracular chambers. The characteristic features of these parts and the moulting processes during the development of the larvae are described in the text. The main features in the development of the third instar larva are the replacement of the epidermal cells by chitin, shortening of the felt chamber and sear cord, increase in the depth of the spiracular chamber, gradual melanization of the posterior spiracle, and then its separation from the dorsal longitudinal trunk prior to pupation.

The larva of Chrysopa, in addition to feeding on aphids, takes a sugar meal from floral nectar, honeydew or, in captivity, solutions of sucrose. Sugar sources are located by a questing activity during which it scans the substrate with the antennae and palps. Feeding on honeydew may lead the larva towards aphids, on which it then proceeds to feed, and this is perhaps a normal sequence in nature.

It is pointed out that this duality of the feeding process — sugar meal and protein-rich meal — seems to be unique among endopterygote larvae, although well known in many adult insects. The larval sugar meal of Chrysopa may be a secondary characteristic which originated from the use of honeydew as an indicator when searching for prey.

The following new genera and species are described: Alatuncusiodes n. gen., type-species A. korytkowskii n. sp., Peru; Argyrarcha n. gen., type-species Boeotarcha margarita Warren, of which Hyaloplaga ankarampotsyalis Viette is a synonym; Mecynarcha n. gen., type-species Mecyna apicalis Hampson; Cymbopteryx pseudobelialis n. sp., Bolivia; Cymbopteryx diffusa n. sp., Mexico; Noctueliopsis decolorata n. sp., Baja California, Mexico; Noctueliopsis grandis n. sp., Baja California, Mexico. Scybalista subductalis Walker is transferred to Alatuncusia Amsel; Thelcteria ysticalis Dyar is transferred to Schacontia Dyar; Edia extralinea Dyar is transferred provisionally to Cymbopteryx Munroe.

Cybalomia angustalis Dognin is transferred to Vdea Guenée; Udea annectans n. sp. is described from Bolivia.

Articulated sensilla occur on the pronotum of 100 species in 65 genera of membracids. The abundance of the sensilla and their universal occurrence in this group suggests that sensory reception is a significant function of the membracid pronotum. Bizarre forms of the pronotum may be a result of selection pressure to increase surface area.

The average rate of diet uptake by the 1st–3rd instar nymphs of the pea aphid, Acyrthosiphon pisum (Harris), on chemically defined diets containing 0.0–5.0% amino acids varied from 0.08 to 0.23 μl/aphid/24 h and that by 4th instar nymphs to adults varied from 0.15 to 0.74 μl/aphid/24 h. The presence of amino acids increased the acceptability of diets to a great extent, as uptake on such diets was 2–5 times more than that on amino acid free diets. Uptake was lowest on diets lacking amino acids, and highest on those containing 3.5 and 2.5% amino acids by 1st–3rd instar nymphs and 4th instar nymphs to adults respectively. It is suggested that certain amino acids, either alone or in combination, act synergistically with sucrose as phagostimulants. Methionine was slightly phagostimulatory to the pea aphid and enhanced the acceptability of a free amino acid diet and of a sucrose solution.

As expected the rate of feeding increased as the aphids grew. Nymphs reached the adult stage, and reproduced on each diet, except on the one lacking amino acids. The longevity on different diets varied from 7 to 37 days. A concentration of 2–4% amino acids, with an optimum at 3.5%, appears to be essential for the growth, survival, and larviposition of the pea aphid.

Due to the punctures made in the stretched parafilm by aphids during feeding the rate of evaporation from fed sachets was significantly higher than that from unfed sachets. It is therefore suggested that in experiments where rates of feeding are measured by differential weighings of the sachets, these be renewed at 24-h intervals.

Field trials were conducted in British Columbia and Oregon in 1972, which demonstrated that trans-11-tetradecenal, a sex attractant for male Choristoneura fumiferana and C. occidentalis, is also a sex attractant for male 2-year-cycle spruce budworm, C. biennis, and that trans-11-tetradecenyl acetate is a sex attractant for male green budworm, C. viridis Free.

The North American species of Choroterpes are discussed and Neochoroterpes n. subgen. is established for C. mexicanus n. sp., C. crocatus n. sp., and C. kossi n. sp. A distribution map is included for the southwestern species of Choroterpes s. str., and distribution map, key to the nymphs, descriptions of the known stages, and figures are presented for the species of Choroterpes (Neochoroterpes).

Individuals of Umbonia crassicornis Amyot and Serville (Homoptera: Membracidae) form aggregations both as nymphs and adults. Each adult female deposits one set of eggs and remains with them. Prior to egg hatching the female moves off the egg mass and makes a series of spiral bark slits with the ovipositor. First instar nymphs aggregate along these slits with the female positioned below the cluster. Adult females use the front tarsi to stroke the backs of moving nymphs to return them to the aggregation.

Adult females remain with the nymphs until they become adults. Aggregations of adults fragment when sexually mature; mating takes place before and during dispersal. Mating behavior consists of four components, the precopulatory position being prolonged.

The genus Masistylum is redescribed. It is recorded for the first time in North America. M. stenommatum n. sp., from the Rocky Mountains of northern British Columbia, is described and figured.

Examination of the most commonly used criteria for separating instars in larval chironomids, based on a study of 29 species from three subfamilies in Marion Lake, British Columbia, revealed that only head capsule width or length is suitable. Most chironomids appear to have four larval instars.

Ths paper describes and illustrates, with photomicrographs, the gross histological development of stages of the endoparasitoid Exoristobia philippinensis Ashmead in the puparia of three synanthropic flies under laboratory conditions. The major organ systems, especially nervous, digestive, reproductive and respiratory are traced.

The following suggestions in use of family-group names for eriophyoid mites are made in accordance with the International Code of Zoological Nomenclature. (1) The name Sierraphytoptidae Keifer 1944 should have priority over Nalepellidae Roivainen 1953 sensu Newkirk and Keifer (1971). (2) The name Diptilomiopidae Keifer 1944 should have priority over Rhyncaphytoptidae Roivainen 1953 sensu Keifer (1961). (3) The superfamily concept of Shevchenko (1968, 1971) should take the name Nalepelloidea Roivainen 1953 rather than Trisetacoidea (a justified emendation of "Trisetoidea") Shevchenko 1968. (4) The names Nalepellidae and Nalepellini should take Roivainen 1953 as author rather than Newkirk and Keifer (1971). (5) Similarly, the names Sierraphytoptini Keifer 1944, Mackiellini Keifer 1946, Diptilomiopinae Keifer 1944, and Trisetacini Shevchenko 1968 should retain their authors and dates as first proposed for new family-group taxa, rather than being new taxa as proposed by Newkirk and Keifer (1971).

Several Schmitt boxes of previously unplaced Platygastridae were made available to me through the kindness of Dr. Paul Marsh, U.S. National Museum. This is the first in a series of papers describing new species and illustrating the types from these and from previously described species.

Corethrella brakeleyi (Coquillett), a haemophagous chaoborid, is recorded for the first time in Canada. Among the insects associated with the larvae of C. brakeleyi was Culiseta melanura (Coq.), a new addition to the mosquito fauna of Quebec.

H. Mourier (1965) described a “novelty effect” in the response of houseflies, Musca domestica L., to a “new object” (usually a 15×15 cm square black tile) placed on the floor of their cage. On its first introduction into their familiar environment, the tile appeared highly attractive and received many visits. The number of visits thereafter decreased and approached a constant level after about 20 min. If the tile was then removed and replaced after an interval of less than 5 min there was no novelty receptivity, but this gradually returned as the time the tile was out of the cage was more and more extended. After 40–60 minutes the response was equal to the “new object” attractiveness. The flies did not seem to miss the tile when it was removed (Mourier, pers. comm., 1971).