Based on bomb calorimeter determinations, the calorific values of four sizes of larvae of Galleria mellonella (L.) fed to nymphs and adults of the predator Podisus maculiventris (Say) increased with increase in larval size. Correspondingly, these values for P. maculiventris nymphs in fourth and fifth instars and adults, male and female, increased when the predator fed on larger larvae. Increases in energy consumption resulted in increases in energy loss due to respiration and egestion for nymphs and adults of the predator. For unfed males and females, calorific values decreased with age, i.e., as initial body energy reserves were used up.No significant differences in mean calorific values were observed for fertile and infertile eggs laid by females reared at each of the four diet levels. This suggests that the amount of energy utilized by females in the production of eggs is fairly constant, irrespective of the amount of energy consumed at each diet level.Energy budgets for nymphs of P. maculiventris showed that gross efficiency of growth for second- and third-instar nymphs was inversely proportional to energy consumed; however, no such relationship was observed for fourth and fifth instars. For males, energy budgets showed that at all diet levels little growth took place during adult fife, with gross efficiency at diet levels 1 to 4 ranging from 0.88 to 2.20%. For females, some growth occurred at all levels of diet during the first 35 days of adult life, mainly as a result of the production of eggs. Gross efficiency during this period ranged from 5.5 to 13.6%. Efficiency of reproduction at diet levels 1 to 4 ranged from 37.26 to 45.35% during the first 35 days of adult life and from 39.46 to 51.16% for the next 20 days.

Larvae of Coleomegilla maculata lengi Timberlake and Leptinotarsa decemlineata (Say) were unable to moult and died after ingesting colloidal silica with their food. Field trials showed that dry silica can be used to reduce populations of L. decemlineata on potato.

Cattle grubs, first-instar larvae of Hypoderma bovis (L.), were removed from nine slaughtered heifers. Two of these heifers had previously been treated with coumaphos, three with Ruelene, and two with trichlorfon. The remaining two heifers were not treated with insecticides and served as sources of control grubs. The grubs, after removal from the hosts and fixation in formalin, were incubated with one of the two cholinesterase substrates, acetylthiocholine iodide or 5-bromoindoxyl acetate. Cholinesterase was completely inhibited in the central nervous systems of the grubs whose hosts were treated with Ruelene. This inhibition was also virtually complete in grubs from heifers treated with trichlorfon and was usually complete in those from the heifers treated with coumaphos. This is presented as histochemical evidence that the three systemic insecticides inhibit the cholinergic enzymes in the grubs, thus causing them to die while still in the body of the host.

In Mexico during the spring of 1950, four imported species of parasitic Hymenoptera (Amitus hesperidum Silvestri, Prospaltella smithi Silvestri, P. clypealis Silvestri, and P. opulenta Silvestri) were placed on populations of their natural host, the citrus blackfly, Aleurocanthus woglumi Ashby. Their artificial distribution and establishment throughout areas in which the host species was extremely abundant and the observed adjustment of each to its host, to its competitors, and to distinctive regional environments revealed physiological and ecological factors that determined the dominance of one species over another. These factors and the circumstances of their occurrence during 1948 to 1953, inclusive, as reported by Herbert D. Smith, Entomologist of the United States Department of Agriculture, are reviewed and amplified.

The behavior of the balsam woolly aphid in relation to its dispersal and establishment is reported. Light orientation trials provided no evidence that crawlers move over their host in a distinct manner. But the number of crawlers that drop from their host increases with light intensity and temperature. Crawler activity may also influence dropping, but activity declines rapidly with increasing age particularly at higher temperatures. Populations along stand edges are probably more subject to long range dispersal.

Glucose, fructose, and sucrose were the only sugars detected in inner bark treated with a southern pine beetle–microorganism complex and two beetle-associated fungi. Treatments drastically lowered the reducing-sugar level. Storage of untreated bolts had no effect on reducing-sugar level; sucrose was lowered but not as much as in treated tissue. Starch content remained unchanged in all treatments.

Results of a qualitative survey of some digestive enzymes of sixth-instar larvae of the pale western cutworm are reported. An extract prepared from the mesenteron (midgut) and its contents showed activity for the enzymes, proteinase, aminopeptidase, dipeptidase, amylase, α-glucosidasc, α-galactosidase, and lipase. There was also evidence for a β-glucosidase activity in the brei prepared from the mesenteron. A brei of salivary glands showed activities for α-glucosidase and amylase, as well as a strong proteinase. These enzymes were not found in brei prepared from the stomodaeum (foregut) or proctodaeum (hindgut). There was no evidence for polygalacturonase, celiulase, β-galactosidase, or carboxypeptidase in any part of the digestive system.Values of pH for extracts from the different parts of the digestive system were: proctodaeum, 7.2; mesenteron, 8.2; stomodaeum, 7.8; and salivary glands, 7.8.

Untreated male tobacco budworms, Heliothis virescens (F.), fail to transfer sperm in about 15–20% of their matings. Tobacco budworms sterilized by 45 krad significantly fail to transfer sperm in about 50% of their matings. Females that received a spermatophore but had no sperm in their spermathecae produced the same numbers of eggs as virgin females. Females with sperm in their spermathecae laid the same numbers of eggs, whether the sperm came from irradiated or untreated males.Irradiated males did not transfer sperm to the spermathecae of the female because sperm were not incorporated into the spermatophore. The failure to incorporate sperm into the spermatophore occurred because the sperm in the male reproductive system did not move from the duplex to the simplex area where the spermatophore is formed. Males irradiated after mating were able to transfer sperm in a second mating as well as untreated males.

The lateralis medius, an indirect flight muscle of Black Hills beetles, degenerated abruptly in females within 3 days after attack. Egg laying began at the end of the 3 days. Thickness of the muscle changed much more than width. Regeneration began in most ovipositing females about 10 days after attack. Steady development of the muscle to its maximum size, reached prior to beetle emergence, offers a method of forecasting emergence.

Laboratory population experiments and theoretical calculations are presented that demonstrate effective population suppression by the introduction of partially sterile cabbage loopers into a native population. The use of partially sterile males is advantageous because they are highly competitive with native moths, and since their progeny are sterile provides for population suppression over at least three generations. It is projected, based on experimental results, that 92% control can be obtained for three generations through a single release of partially sterile males. This modification of the sterile-male technique for Lepidoptera could result in control and sizeable savings in cost. Insecticide and other forms of control can be used simultaneously without any effect on the efficiency of the release program.

A key is given for seven species of Aphis L. that occur on Cornus species in North America: caliginosa Hottes and Frison, corniella (Hille Ris Lambers), cornifoliae Fitch, helianthi Monell, maculatae Oestlund, neogillettei Palmer, and a new species that is described, nigratibialis Robinson. Host transfer attempts with helianthi and corniella are discussed.

Paired mandibular mycangia are present in both sexes of the bark beetle Dryocoetes confusus Sw. These fungus repositories were not found in either sex of another bark beetle of the same genus, Dryocoetes affaber Mann.

The oviposition behavior of the pteromalid parasitoid Nasonia vitripennis (Walker) was investigated in an attempt to explain the difference in population density maintained on two species of host, the housefly, Musca domestica L., and the blowfly, Phaenicia sericata (Meigen). The behavior of a female wasp was significantly affected by the species of host to which she was exposed. When presented with 10 pupae for 24 hours she averaged 14.2 eggs on 3.0 housefly hosts and 8.3 eggs on 7.2 blowfly hosts of the same size.The importance of the alteration in behavior to the population density of Nasonia became apparent when the suitability of the two host species was examined. At all densities of eggs more wasps matured on blowfly pupae than on housefly pupae of the same size. Survival on both hosts decreased as the density of Nasonia eggs increased. The difference in egg distribution, coupled with lower survival on housefly pupae and at increased density suggests a considerably lower production by this parasitoid on housefly hosts, compared with that on blowfly pupae.

The larvae of Culicoides denningi F. & P. may be unique among Ceratopogonidae in that they appear to be restricted to rivers. In the South Saskatchewan River the larvae overwinter in the sand across the entire river bed. Several weeks after the ice breaks up in the spring the larvae swim to shore to pupate. Man and livestock near the river are sometimes severely attacked.

A new species of Eremocharis (Orthoptera: Pamphagidae) is described, E. zaheri, from Paktia Province, Paywar, Afghanistan.

The description of a new species of Phytodietus, subgenus Neuchorus, is presented. A closely related species is transferred to Neuchorus, also, and a key is provided to separate the two.

Single females of Spalangia drosophilae Ashmead searching for 80 puparia of Hippelates collusor (Townsend), arranged in clumped or linear distributions, oviposited randomly producing equal numbers of progeny from cither host arrangement. Mixed groups of linear and clumped puparia caused changes in behavioral patterns that resulted in reduced progeny production, thus showing parasitization to be nonrandom. Host destruction was, nevertheless, greater in an all-clumped distribution, tile greater acceptance of clumped groups resulting in a greater number of progeny. Mixed groups involving a choice between linear or clumped distributions demonstrated the greater acceptance of clumped groups. Direct observation showed that the all-dumped distribution elicited the greatest overall initial attraction for hosts and subsequent movement to other areas. It was concluded that maximum host destruction resulted when completely random behavior was involved. A recognition of this, however, required a knowledge of behavior, host condition, and progeny production. The question of evaluating an exotic parasite’s effectiveness before introduction is discussed.

Betulaphis viridis is described and illustrated. It is a bright green species that occurs on the upper surfaces of the leaves of Betula pendula Roth and is known only from Ontario.