Females of species in Cicindela have a groove or pit in the mesepisternum which is concluded to be a mating structure, "coupling sulcus," that is held by the mandibles of the male. Six character states of the coupling sulcus are described, and may be useful for identification at the species and species group levels. Primitive (groove) and advanced (cavity) states of the coupling sulcus are derived by comparison with a classification of North and South American Cicindela based on the male genitalia. I suggest the following hypothesis: the female mating structure evolved in response to the highly agile behaviour of diurnal tiger beetles; the advanced cavity-like coupling sulcus is a result of population adjustments to long periods of hot conditions; and the non-agile, crepuscular, and nocturnal habits of primitive tiger beetles such as Amblycheila, Omus, and Megacephala have resulted in no selection for a female mesepisternum coupling sulcus.

The signaria group of the genus Semiothisa is a complex of 10 extremely similar species, most of which are host-specific on certain genera of coniferous trees An eleventh species, S. sexmaculata, is also treated in this revision because of its close resemblance to members of the signaria complex, although its true affinity appears to be with the liturata–bisignata group. The species are described and illustrated, and their synonymy, distribution, variation and biology are discussed in detail, including an account of industrial melanism in a population of S. pinistrobata. Two new species names are proposed, and eight lectotypes designated. The main center of distribution is northeastern North America, and all of the known species except S. fuscaria occur on this continent. The one Holarctic species, S. signaria, which is generally the commonest in collections, also has the widest range of host plants, feeding on at least six genera of coniferous trees.

Two chalcidoid species, previously known only from Europe, are reported from North America for the first time. Habritys brevicornis (Ratz.) occurs in Quebec, Ontario, and British Columbia. Psilonotus achaeus Wlk. (= Eutelus betulae Grit., new syn.) occurs in Ontario, New York, and Michigan; it parasitizes Oligotrophus betulae Winn. (Cecidomyiidae) in seed of white birch.

Four species have been described in the apterus-group of the staphylinid genus Tachinus Gravenhorst. One of these, tundrae Poppius, is regarded as a synonym of brevipennis Sahlberg. Tachinus arcticus (Motschulsky) is recognized as a valid species, although earlier works have considered it a synonym of apterus. Tachinus brevipennis is recorded from the Nearctic Region for the first time. A neotype is designated for arcticus and lectotypes are designated for brevipennis and tundrae. Tachinus instabilis Mäklin is transferred to the apterus-group from the fimbriatus-group and recorded for the first time from Siberia. One new species, T. glacialis, is described from Siberia.

A key for identification of the species of the group and a description of the group characters are included. Each of the five species is described and the major diagnostic characters illustrated with scanning electron photomicrographs. A map is included to show the distribution of the species.

Sequent sampling of adult males of Atractomorpha sinensis sinensis Bolívar from a laboratory culture has shown that the phallic structures become progressively sclerotized with age, resulting in changes in form, mass, and rigidity which continue throughout adult life. This confirms what had been deduced from previous taxonomic studies. It not only has important implications for taxonomy, but may be a factor affecting reproductive activity of the insects.

Euxoa antica, closely related to Euxoa terrena (Smith), is described from western United States. Adults and genitalia of both species are illustrated.

Noctueliopsis rhodoxanthinalis, a striking pink and yellow species from western Texas, is described as new. It is not close to any described species, but is compared with N. pandoralis (Barnes and McDunnough, 1914), Mojavia achemonalis (Barnes and McDunnough, 1914), and Mojaviodes blanchardae Munroe, 1972.

Calling by newly emerged female Lambdina fiscellaria lugubrosa (Hulst) began the first evening and commenced 15 h after the onset of light in nature and in a 14L:10D photoperiod regime in the laboratory. Copulation began 0.5 to 1.5 h later, and moths remained in copulation an average of 3.45 h. The internal reproductive system is typical of ditrysian-type Lepidoptera. Mating usually resulted in the transfer of a single, spheroid spermatophore with a long collum. The spermatophore was placed in the bursa copulatrix in such a position that spermatozoa could leave through the aperture into the ductus seminalis. The greatest mating success occurred between 2- to 4-day-old males and females up to 4 days old. Maximum oviposition occurred on the day after mating. Numbers of eggs maturing and being laid were increased after mating. Mean longevity of mated and unmated females in the laboratory was 18.1 and 20.8 days, respectively. Mating success was greatest at a 6:1 male to female sex ratio, and progressively less at a 1:1 and 1:6 sex ratio. Males mated only once in a 24-h period, but were capable of multiple mating. Females usually accepted one spermatophore but occasionally up to three were found.

The composition of the tachinid genus Allophorocera, including species formerly placed in Erycilla and Pilatea, is discussed and a key to the Palaearctic species is provided. Allophorocera lapponica n. sp. from Kilpisjärvi, Finland, is described and figured.