Ultrastructure of attachment specializations of hexapods (Arthropoda): evolutionary patterns inferred from a revised ordinal phylogeny Author R. G. Beutel Author S. N. Gorb text J. Zool. Syst. Evol. Research 2001 39 177 207 journal article 10.1046/j.1439-0469.2001.00155.x 95b3d62f-8fcc-4088-873f-b33f4a63d3fc 2360323 28 Coleoptera Tarsi are five­segmented in most groups of Coleoptera . However reduction in number of tarsomeres occurs in several lineages (e.g. Chrysomeloidea). The ventral side of the proximal tarsomeres is covered with a very dense layer of hairs in males or both sexes of many coleopteran species ( Fig. 3d , 5B,G,H ). This is considered as a groundplan feature of the order. Tarsal hairs are transformed into larger or smaller suckers in representatives of some aquatic groups of Adephaga such as Gyrininae and Dytiscinae . In Priacma serrata (Archostemata), the hairs are branched in a feather­like pattern ( Fig. 5C,D,F ). Arolium, pulvilli, and euplantulae are absent from adults and most larvae of Coleoptera . An arolium­like structure is present in larvae of Chrysomelidae ( Gannon et al. 1994 ) .