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. The genus Pseudochakura Ashmead (Eucharitidae: Eucharitinae) is revised to include thirteen species which all share the complete fusion of the genae behind the mandibles and a loss of functional mouthparts. Eight Neotropical and one Nearctic species of Pseudochakura are described as new: atra (Mexico), condylus (lesser Antilles), excruciata (Brazil), frustrata (Argentina), liburna (Florida, U.S.A.), pauca (Argentina), prolata (Argentina), sculpturata (Brazil; Florida, U.S.A.), septuosa (Mexico). P. chilensis Kieffer is redescribed. The known distribution of P.nigrocyanea Ashmead is extended to Uruguay and Venezuela. The known distribution of P. americana (Howard) [comb.n.] is extended to Panama, Columbia, Ecuador, Argentina and northward into the southern tip of Florida. All three previously described Nearctic species are synonomized under the name P.gibbosa (Provancher) with P.arizonensis (Crawford) and P.californica (Ashmead) as junior synonyms. Biological information is summarized providing new information on both plant and ant hosts. A phylogenetic hypothesis for the genus is nresenteri. [ABSTRACT FROM AUTHOR]

Variation in structures of the posterior surface of the head in Hymenoptera is compared and interpreted according to theories of head capsule evolution, with focus on understanding previously baffling conditions in the superfamily Chalcidoidea. Features are investigated separately without first classifying subforaminal bridges into subcategories. In Proctotrupomorpha (including Chalcidoidea), Ceraphronoidea and some Ichneumonoidea, there are multiple posterior pits associated with the tentorium. In most examined Hymenoptera with a subforaminal bridge, there was a differentiated median area, typically with highly variable microtrichia. This area is elevated in Cephoidea and Pamphilioidea, but is not elevated in other Hymenoptera. Subforaminal bridges in Apocrita previously classified as hypostomal bridges are discussed in the context of A.P. Rasnitsyn's hypothesis that relative importance of adult feeding drives subforaminal bridge evolution., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Bean thrips, Caliothrips fasciatus, is native to western North America. Once considered a pest of several crops in its native area, its pest status has waned over recent decades. However, due to its habit of aggregating in the navel of navel oranges, bean thrips remains economically important because some countries importing oranges from California have designated it a quarantine pest. Despite continued propagule pressure, bean thrips has never established outside North America. We examined genetic variation in mitochondrial DNA among Californian populations of C. fasciatus and found that potentially two cryptic species are present (supported by Kimura 2-P distances): a common widespread form B and a rarer form A with a very limited distribution. Form B showed strong phylogeographic structure, with many haplotypes having a limited geographic distribution. Inter-population crossing experiments between three geographically isolated populations of form B resulted in the production of some female offspring, indicating a degree of compatibility between these populations of this haplodiploid species. However, substantial outbreeding depression was also detected. A low frequency of offspring production by hetero-population pairs was evidence of pre-mating isolation, while post-mating isolation was also evident in the elevated mortality of fertilized eggs in successful hetero-population crosses. One surprising finding was the total lack of offspring production by virgin females when isolated individually. However, virgin females did produce sons in the presence of other virgin females. A test for the presence of Wolbachia showed that form B was not infected, but that some populations of the rarer form A were.

Species of Encarsia Förster (Hymenoptera: Aphelinidae, Coccophaginae) are economically important for the biological control of whitefly and armored scale pests (Hemiptera: Aleyrodidae, Diaspididae). Whereas some regional keys for identification of Encarsia species are now available, few studies have addressed relationships within this diverse and cosmopolitan genus because of unreliable morphological data. Nuclear sequences of the D2 expansion region of 28S rDNA were determined from 67 strains of 24 species representing 10 species groups of Encarsia, 2 strains of Encarsiella noyesi Hayat, and 1 strain of Coccophagoides fuscipennis Girault. Analysis of molecular data alone and combined with morphological data resolves many nodes not resolved by morphology alone and offer insights into which morphological characters are useful for supporting group relationships. All analyses that include molecular data reveal Encarsia to be paraphyletic with respect to Encarsiella. If monophyly of Encarsia is constrained, the relationships are the same but with a different root within Encarsia, and these trees are presented as an alternate hypothesis. The luteola and strenua species groups are shown by both morphological and molecular data to be monophyletic, whereas the inaron group, the E. nigricephala + luteola group, and the E. quericola + strenua group are supported only by molecular data. The aurantii and parvella species groups are not supported in any of the analyses. The utility of morphological characters for defining species group relationships is discussed., (Copyright 2001 Academic Press.)