A phylogenetic analysis of generic relationships and revised generic concepts for the Trigonalidae is presented. The Trigonalidae is divided into two subfamilies, the Orthogonalinae and the Trigonalinae. Orthogonalinae consists of a single primitive genus, Orthogonalys, sharing many generalized apocritan characters, but lacking advanced trigonalid characters including antennal tyloids and female metasomal armature. No synapomorphies have been detected for the Orthogonalinae. Trigonalinae are characterized by the presence of tyloids. The Trigonalinae were originally defined by the absence of female armature, and were therefore polyphyletic because armature has been lost several times. Within the revised concept of Trigonalinae, the tribe Trigonalini is characterized by the presence of elongate parameres and an intertorulus distance subequal to the distance between the torulus and the eye. A second tribe, Nomadinini, is based on the secondary loss of tyloids, and comprises the previous subfamilies Seminotinae, Nomadininae, Bareogonalinae and Lycogastrinae. The two tribes Trigonalini and Nomadinini share the presence of female armature, although in some Trigonalini it has been secondarily lost. The genera Labidogonalos Schulz, Lycogastroides Strand, Lycogonalos Bischoff, Nanogonalos Schulz, Poecilogonalos Schulz and Taiwanogonalos Tsuneki are synonymised under Taeniogonalos Schulz. The species Lycogaster zimmeri Bischoff, Tapinogonalos maschuna Schulz, and Trigonalys pictifrons Smith (placed in Lycogaster by Schulz, 1906a) are transferred to Taeniogonalos. The genera Discenea Enderlein and Stygnogonalos Schulz are synonymised under Trigonalys Westwood. The species Labidogonalos flavescens Bischoff, L. sanctaecatharinae Schulz, Trigonalys lachrymosa Westwood (placed in Lycogaster by Bischoff, 1938), T. maculifrons Cameron (placed in Labidogonalos by Bischoff, 1938) and T. rufiventris Magretti (placed in Lycogaster by Schulz, 1907a) are transferred to Trigonalys.Trigonalys costalis Cresson is synonymised with Taeniogonalos gundlachii (Cresson). Xanthogonalos fasciatus Bertoni and X.severini Schulz are synonymised with Trigonalys sanctaecatharinae (Schulz). Mimelogonalos partiglabra Riek and M. punctulata Riek are synonymised with M. bouvieri Schulz. Lectotypes are designated for Trigonalys melanoleuca Westwood and Taeniogonalos fasciatipennis (Cameron). The author of Trigonalys maculifrons is Sharp (1895), not Cameron (1897), and the author of Taeniogonalos enderleini is De Santis (1980), not Schulz 1906. Viereck (1914) designated Trigonalys pulchella Cresson as type of the genus Tapinogonalos Schulz, preceding Bischoff's (1938) designation, making Tapinogonalos a synonym of Orthogonalys. A new genus, Afrigonalys, is proposed for the three species that were described in ‘Tapinogonalos’sensu Bischoff, nec Viereck.

We inferred a phylogeny for the walking-stick genusTimema (Insecta: Phasmatoptera) using mitochondrial DNA sequence, and we used the phylogeny to infer temporal patterns of speciation and the evolutionary history of parthenogenesis. Maximum parsimony, neighbour-joining and maximum-likelihood analyses of 660 base pairs (bp) of cytochrome oxidase I (COI) yielded phylogenies that were well resolved and topologically identical or very similar. Application of an insect molecular clock for COI suggests that the genus originated in southern California, northern Mexico or Arizona about 20 million years ago and underwent a burst of speciation 1.5^3 million years ago during the uplifts of the Sierra Nevada, Coast, and Transverse Ranges. The phylogeny indicates that the three parthenogenetic lineages of Timema have arisen independently and are each closely related to morphologically indistinguishable or similar sexual species. Each of the three lineages exhibits an allopatric or parapatric, and more northerly, distribution with regard to their closest sexual relative. COI divergence levels between each of the three parthenogens and their closest sexual relative suggest ancient origins of parthenogenesis, 1.5^3 million years ago, that may coincide with the extensive glaciation that formed the North American ice sheets.

About 300 species of thrips belonging to 57 genera are known to form galls. Galls are caused by feeding, usually by one or more adults, on actively growing plant tissue. Most thrips genera with galling capabilities exploit multiple plant families, but there are several possible cases of thrips tracking the speciations of their host-plants. Gall morphology in thrips reflects insect phylogenetic relationships rather than those of plants. Galling species and their nongalling allies on Acacia in Australia exhibit a range of complex social behavior, including soldier castes, pleometrosis (i.e. joint colony founding), group foraging, and group defense, that is directly related to the nature of their domiciles. Galling thrips, by virtue of their haplodiploid genetic system and their ecological relationships with plants and natural enemies, are useful for analyzing a wide range of ecological, evolutionary, and behavioral questions.

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