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.

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.

Three new species of Pityophthorus Eichhoff (Coleoptera: Scolytidae) are described from Canada: aquilonius from the Yukon Territory, collinus attacking Pinus albicaulis in British Columbia, and orarius attacking Pseudotsuga menziesii in British Columbia.

In Tanyderidae, Blepharoceridae, and Cylindrotominae, the aedeagus of the male carries three seminal ducts which open independently. In the female, similarly, there are three spermathecae and their ducts lead to independent openings on the ninth sternum, spaced to correspond to those of the male. The aedeagal ducts are very narrow and arise from an ejaculatory pump supplied by the common duct of the testes; and during mating the aedeagal openings are closely applied to the spermathecal openings or inserted into the spermathecal ducts. The ejaculatory pump and closed system during mating occur in many, but not all, Nematocera and perhaps throughout the Brachycera, but the tripartite condition of the organs of sperm transfer is reduced to a bipartite condition in Phlebotominae and to a ’simple’ condition, with only a single opening of the aedeagus and spermathecal system, in nearly all other Diptera. The spermathecae themselves, however, remain three in number almost throughout the order, though their ducts unite before opening; and this pattern must have been derived from the tripartite pattern of the Tanyderidae, etc., which represents the basic condition in the order.

In the Culiciformia (Culicidae, Chironomidae, Simuliidae, etc.) on the other hand, there is no ejaculatory pump but its place is taken by a wide duct lined with folded cuticle and covered by a muscular coat. The aedeagus is not suited for close apposition to the spermathecal opening. During mating a larger quantity of sperm-containing material is deposited in the surrounding atrium, as a liquid (Culicidae) or often as a spermatophore. Sperm transfer can be completed rapidly, as the pair meet in flight in the swarm. One primitive family, the Dixidae, constitutes an exception to these generalizations.

The Bibionomorpha, except for Anisopus, were not studied.

A brief comment is made on the characteristic small size of the dipterous spermatheca and the fineness of the spermathecal ducts.

Progressively increasing lengths of exposure to pure nitrogen caused temporary anaesthesia, irreversible partial paralysis, and death, in that order, to the European red mite, Panonychus ulmi (Koch). The immature stages, especially eggs, were more tolerant than adult females. Confinement in 2.5% oxygen at a relative humidity approximating 100% had no effect on the mites, except on oviposition, beyond that of high humidity alone.

This study includes the first published record of a berothid life history and the first description of a second instar larva. The incubation period was 7 days (N = 21), and the median durations of the first and third stages were 12.5 days (N = 8) and 20.8 days (N = 5). The length of the second stadium was 3 days (N = 5). One adult emerged, after being within the cocoon for 20 days (all temperatures, 75±3°F).

Eggs were laid in a stalked cluster in which there were fewer stalks than eggs. The first and third instars, which have piercing–sucking type mouthparts, were carnivorous and fed on the termite Zootermopsis angusticollis. Both of these stages were very mobile. On the other hand, the second instar, apparently a non-feeding stage, hung downward by the abdominal tip. It was not active except when disturbed, whereupon the body snapped into a straight position and then back again into the original C-shaped attitude. The cocoon was oval and transparent.

Viability decreased with successive instars and it is possible that the prey offered to the immatures was an inappropriate termite species and therefore a suboptimum food source. It is also likely that unfavorable physical conditions contributed to the high mortality of the immatures.

Both the second and third instar larvae are described, and the third instar is compared with a previously described third instar larva of an undetermined species within the same genus.

Overwintering adult T. lineatum were collected in late April, and the females allowed to attack Douglas-fir logs in the laboratory. Frass was collected and preserved at −40°C prior to extraction in benzene and distillation. Distillate was chromatographed in a silica-gel column. An olfactometer was developed in which a positive bio-assay involved arrestment and turning reactions in a runway over a perforated area, underneath which the test substance was placed. Responses occurred to female frass and to sawdust from host logs but frass was far more potent. Peak response occurred to frass produced within 4 to 8 hours after attack. After 2 weeks, only very small amounts of weakly attractive frass were produced. Benzene extract and distillate of female frass evoked trace responses at very low concentrations, hut at 3.2 × 10−2 and 7.4 ×10−3 g-equiv of frass, for extract and distillate respectively, responses over 70% were common. Two fractions of ether eluate from the silica-gel column contained a highly attractive component which evoked responses in about 70% of the test males.

Leiparthrum albosetum n. sp. from Baja California is described. The three North American species in the genus are discussed and a key to distinguish them is presented.

The sex ratio of the polygamous species Ips acuminatus (Gyllenhal) varied in 31 localities of Norway from 1 to 4 females per male in northern and western areas to 20 females and more in some southeastern areas. The number of female galleries per nuptial chamber (usually three to five) varied accordingly and isolated female galleries were also formed. Laboratory breedings showed that the species has two types of females, one which produces only females and one which produces both-sixes usually with a 1:1 sex ratio.

The acid and alkaline phosphatase activity was measured in the developing egg and in the alimentary canal of aging nymphs as well as adult males and females of different ages. Para-nitrophenol was used as colorimetric standard and disodium p-nitrophenyl phosphate as substrate. Activity was measured in terms of micromoles of p-nitrophenol liberated from the substrate as a result of enzyme action.

Acid phosphatase activity was noticed to increase with the embryonic development and was higher than in the case of alkaline phosphatase. The alkaline phosphatase activity was lowest in the freshly laid egg, but increased more sharply than acid phosphatase during embryonic development.

The activity of both the acid and alkaline phosphatases was highest in the first instar and declined gradually to the fifth instar. The activity of acid phosphatase was higher than alkaline phosphatase in all stages except the first instar where it was almost equal. The activity of both the enzymes was higher during the intermoulting period and declined at each moult indicating a hormone–enzyme relationship.

In adults, activity of both the enzymes increased up to the maturation period after which the activity gradually decreased. Acid phosphatase activity was generally higher in males whereas alkaline phosphatase activity was generally higher in females. In almost all cases, the acid phosphatase activity was found to be higher than the alkaline phosphatase.

The ecology and evolution of the parasite (Nasonia vitripennis Walker) and host (Musca domestica L.) were investigated in a specially designed multicelled population cage which provided ample space–time structure to the environment for free parasite–host interactions. The population characteristics exhibited by a control or newly associated parasite–host system were compared with an experimental parasite–host system which already had evolved a degree of ecological homeostasis. Population fluctuations in the experimental parasite population were dampened compared with the control parasite population which fluctuated with great intensity; and in addition, the mean number of parasites in the experimental systems was significantly lower (about 1/4) than the mean number of parasites in the control system.

Oligotrophus papyriferae Gagné is univoltine in Michigan. Adults emerge in mid-May and the females deposit small egg clusters on the underside of the leaf near the petiole of paper birch (Betula papyrifera Marsh.). Larval eclosion occurs 1–2 weeks later; there are three instars. The larvae bore into and down the petiole and enter the stem or a bud attending the leaf base. Galls appear in early August. There are petiole-bud and petiole-stem galls, depending on which tissues are infested. Third-instar larvae vacate the galls in late September, work their way into the litter, and construct cocoons in which they overwinter. Pupation occurs the following May. Trees from 2 to 30 ft tall are attacked; lower branches are attacked the heaviest. Large galls kill buds, twigs, and entire branches. Small galls leave deeply indented branch scars and deformed limbs.