Revision of the larvae of Leptus Latreille (Acarina: Erythraeidae) of Europe and North America, with descriptions of post-larval instars

Abstract

The larvae of Leptus Latreille, 1796 (Acarina: Erythraeidae) of Europe and North America are comprehensively revised. Of those described since 1900 a total of 34 species is considered recognizable and capable of being keyed; no species described before 1900 is considered recognizable. The nominal type of the genus, Acarus phalangii de Geer, 1778 is rejected as an illegitimate name. Eighteen European and 17 North American species are described and keyed, of which 17 are new to science. One new subspecies from North America, of a species previously known from Europe, is described and keyed. Standard metric data are given for each species or subspecies from available specimens (except two North American species, L. ariel Southcott and L. clarki Southcott, recently described elsewhere; for these last-named two additional metric data are given). Larvae have been recorded from April to September, with the greatest number found being for July and August. Protonymphs are described for two North American species (L. ghiradellae sp. nov. and L. welbourni sp. nov.), and deutonymphs for two North American species (L. calix sp. nov. and L. ghiradellae). Keys are given to separate the reared protonymphs, and three described deutonymphs (the two preceding and the European L. galerucae Feider). Data on the duration of the protonymphal instar suggest that in North America and Europe there are two modes: one lasting 3–4 weeks, the other 5–7 months. Developmental abnormalities are recorded systematically.