A new species of Dactylopius Costa (Dactylopius gracilipilus sp. nov.) (Hemiptera: Coccoidea: Dactylopiidae) from the Chihuahuan Desert, Texas, U. S. A. Author Van, Alex R. Author May, Bernie text Zootaxa 2012 3573 33 39 journal article 10.5281/zenodo.283009 6ba5b491-99e6-439b-a4e3-6f25c18174e7 1175-5326 283009 Dactylopius Costa, 1835 Dactylopius Costa, 1835 :16 Selected reviews: De Lotto 1974 ; Perez Guerra & Kosztarab 1992 ; Claps & de Haro 2001. Type species: Dactylopius coccus Costa, 1835 . Generic diagnosis. Synapomorphic characters that define adult female Dactylopiidae include: presence of numerous truncate setae over dorsal surface of abdomen; quinquelocular pore clusters on a sclerotized plate each frequently associated with one or more tubular ducts. Distribution. Dactylopius has been introduced both accidentally and intentionally into many parts of the world where suitable habitat occurs ( Portillo & Zimmermann 2008 ). Dactylopius is native to arid regions of the western hemisphere where native cacti, especially opuntioid cacti, occur. Diagnosis. Dactylopius gracilipilus sp. nov. keys out to D. tomentosus (Lamarck) in couplet 5 in Perez Guerra and Kosztarab (1992) . Below is an additional couplet to include D. gracilipilus . 5 Truncate cylindrical setae forming medial and submedial longitudinal rows on thorax and abdomen................... 5b - Truncate setae not forming various rows................................................................... 6 5b Large stout setae with parallel sides each less than 1.5 times as long as wide, present in medial and submedial longitudinal rows; simple pores entirely absent or rare on dorsum of abdomen; 10 or more wide-rimmed quinquelocular pores per cluster uncommon, and not forming distinctive transverse bands; host-plant Cylindropuntia spp.................. D. tomentosus - Large truncate setae with parallel sides each 1.5–2 times as long as wide, present in medial longitudinal rows, submedial rows less distinctive and made up of smaller setae; dorsum with abundant simple pores; clusters of wide-rimmed quinquelocular pores with more than 10 pores per cluster common, forming distinctive transverse bands; host-plant Corynopuntia spp........................................................................................ D. gracilipilus sp. nov.