A group of tarsonemid mites, which are egg parasites of ipine bark beetles, is reviewed on a Holarctic basis. The genus Iponemus (new name for Moseria Beer and Nucifora) is proposed and described for the group, and 24 species or subspecies, including 19 described as new, are described, keyed, and illustrated. A detailed species-group description follows the generic description, and includes several structures hitherto not reported for species of Tarsonemidae. The variation and usefulness of the few characters available for distinguishing forms of Iponemus is discussed, and the provisional treatment of some forms as species and others as subspecies is explained.These mites are among the most host-specific associates of scolytid beetles: 16 of the 18 species or subspecies of Iponemus associated with the nearctic, pine-feeding ipines are monospecific, and each of the other two is restricted to two closely related species of hosts. The mites and the beetles together are considered with regard to size correlations, the degree of host specificity, the mites as taxonomic indicators of their hosts, biogeography, life history, and the role of egg parasitism by the mites in the population regulation of their hosts.

In North America the genus Cephalcia Panzer includes 10 species. The californica group, californica Middlekauff, frontalis (Westwood), fulviceps (Rohwer), and probably hopkinsi (Rohwer), has large species with gregarious larvae which build frass nests on Pinus. The provancheri group, distincta (MacGillivray), provancheri (Huard), semidea (Cresson), and probably nigra Middlekauff, has smaller species with solitary larvae that build silk-tube shelters on Picea, Abies, or Tsuga. Two species fit in neither group: fascipennis (Cresson), a large species with weakly gregarious larvae that build frass nests on Picea, and marginata Middlekauff, a small species quite unlike those of the californica group, with gregarious larvae that build frass nests on Pinus. Californica and hopkinsi are western species, provancheri and fascipennis are transcontinental, and the others are eastern. Keys are given for larvae and adults.The immature forms are described; the larva of fascipennis in detail. Females have one more instar than males.The eggs of all species are laid on needles of the host tree with a small knob-like part inserted into the host tissue. The larvae, which eat previous years' foliage, develop rapidly and drop to the ground when through feeding. Larvae do not construct cocoons but overwinter in a cell formed in the soil. Pupation and emergence may occur the next spring, or after two or more winters in the soil.Sex is determined by whether or not the egg is fertilized, thus parthenogenesis is facultative and arrhenotokous. An exception is semidea, having thelyotokous parthenogenesis and no known males.

Bionomic and phylogenetic research on the Tabanidae is hampered by an inadequate knowledge of their immature stages, the larvae and (or) pupae of only 154 of the approximately 2000 world species being known. The present study is an attempt to partially rectify this situation in North America where it is almost as acute as elsewhere.By means of hand-searching or using a specially designed sieve and multiple Berlese funnel, larvae were obtained from 219 wetland habitats of various types in Ontario, New York, Pennsylvania, Vermont, and New Jersey. Many of the larvae were then reared to the adult stage to provide conclusive species identification. During the rearings larval and pupal exuviae were retained and preserved. These together with accurately associated whole preserved larvae and the immatures of several species obtained from other sources were the basis for detailed general descriptions of tabanid larvae and pupae, keys and diagnostic descriptions of these stages as well as descriptive comments on the habitats of the 36 species of Chrysops, 1 Merycomyia, 19 Tabanus, 7 Atylotus, and 18 Hybomitra which are included in the paper. The larvae and pupae of 43 species are described for the first time.In discussing the phylogenetic implications of these larvae and pupae several evolutionary trends and the high degree of concordance between these stages and the adults is pointed out, which lends considerable support to the present classification based solely on adults. The non-alignment of the immatures of some species suggests their improper placement. However, this cannot be proved until the immature stages of many more species covering a broader spectrum of the family are known.Parasitism involving Carinosillus tabanivorus (Hall) (Tachinidae), Villa lateralis Say (Bombyliidae), Diglochis occidentalis Ashm. (Pteromalidae), and Trichopria sp. (Diapriidae) accounted for approximately two per cent of the mortality of reared specimens.

A revised generic classification of world Syrphini is proposed. It is based on a study of characters of the adults of 318 described species plus approximately 85 more species as yet either undescribed or unidentified. Thirty-seven genera are recognized; keys to these genera, and to the smaller number of genera known from each of the major zoogeographic regions (except the eastern Palaearctic and Oriental) are presented. Eight new genera, Notosyrphus (South America), Exallandra (Ethiopian Region), Citrogramma (Oriental Region and Australia), Dideomima (Mexico), Hermesomyia (Ecuador), Pseudoscaeva (North and South America), Antillus (Haiti), and Giluwea (New Guinea), and two new subgenera, Melangyna (Austrosyrphus) (Australia and New Zealand) and M. (Melanosyrphus) (New Guinea), are described. Nine new species, in Melangyna (Melanosyrphus), Citrogramma, Hermesomyia, Antillus, and Giluwea, are described. The genus Orphnabaccha is transferred from the tribe Bacchini to the Syrphini, and the genus Toxomerus (including Mesograpta) is referred to the tribe Toxomerini. Maps showing the world distribution of each genus and subgenus, and figures of the male terminalia of the type-species of almost all genera and subgenera, are presented.The peculiar nature of the Neotropical fauna of Syrphini, with almost all species belonging to two large and very diverse genera, is compared with the situation in the rest of the world, where in most major regions the Syrphini consist mostly of a moderate number of medium-sized genera each of which shows much less diversity. Possible reasons for this difference, and for the great preponderance of more primitive Diptera among those with apparent transantarctic relationships, are suggested.

New Guinea was found to belong to the Australian Region in the classical sense of Wallace insofar as its fleas are concerned. Fifty-eight species, 28 more than hitherto recorded from New Guinea, are discussed, belonging to four families. Six species, representing three families, originated in the Oriental Region or in continental areas contiguous to it, and 52 species, comprising 15 genera of the Pygiopsyllidae, had their primordial evolutionary connections with Australia. There is much endemism of pygiopsyllids in New Guinea, all of the species and 11 of the genera occurring only there, where they are mostly associated with marsupials and murid rodents. The following genera are described as new: Orthopsylloides (type: Stivalius abacetus Jord. and Roths.), Parastivalius (type: Ceratophyllus novaeguineae Roths.), Papuapsylla (type: P. luluai n. sp.), Striopsylla (type: Stivalius rugatus Jord.), Metastivalius (type: Pygiopsylla mordax Roths.), Obtusifrontia (type: O. simplex n. sp.) and Rectidigitus (type: R. traubi n. sp.). The following new combinations for described species in these genera are proposed: in Parastivalius, Stivalius gracilentus Jord.; in Papuapsylla, Stivalius corrugis Jord., S. alticola Jord. and S. papuana Jord. & Roths.; in Metastivalius, Stivalius anaxilas M. Roths., S. lasiurus Jord. & Roths., and S. shawmayeri Jord.; and in Rectidigitus, Stivalius spooneri M. Roths. and S. ancisus Jord. In addition, descriptions of the following new species or subspecies are presented: Porribius papuanus (Ischnopsyllidae), Acanthopsylla aiyurensis, A. monticola, A. eudromiciae, A. bisinuata, Hoogstraalia novaeguineae, Pygiopsylla spinata, P. laciniosa bismarckensis, P. archboldi, P. smitiana, P. traubi, Traubia vandeuseni, T. peristigma, T. kuru, Orthopsylloides o. orthodactylus, O. o. owiensis, Parastivalius brassi, P. gressitti, Papuapsylla barretti, P. minor, Striopsylla vandeuseni, Metastivalius huonensis, M. rothschildae, M. tamberan, and Rectidigitus szentivanyi (Pygiopsyllidae).The hitherto unknown males of Acanthopsylla enderleini (Wagn.), Pygiopsylla l. laciniosa Roths., and Orthopsylloides abacetus (Jord. & Roths.) and the females of Papuapsylla corrugis (Jord.), Striopsylla rugata (Jord.), and Metastivalius anaxilas (M. Roths.) are described.