Trophobiosis between a new species of Williamsrhizoecus (Hemiptera: Coccomorpha: Rhizoecidae) and Acropyga silvestrii (Hymenoptera: Formicidae) in Tanzania Author Schneider, Scott A. USDA, Agricultural Research Service, Henry A. Wallace Beltsville Agricultural Research Center, Systematic Entomology Laboratory, 10300 Baltimore Avenue, Beltsville, Maryland 20705, USA. Author Lapolla, John S. Department of Biological Sciences, Towson University, 8000 York Road, Towson, Maryland 21252, USA. text Zootaxa 2020 2020-09-22 4853 2 283 291 journal article 8429 10.11646/zootaxa.4853.2.9 84f6c00b-9633-4481-a98e-e06b766c39c7 1175-5326 4410715 DEAF3CA3-6B57-4695-9D97-6838C2103810 Key to species of Williamsrhizoecus based on the adult female Based on keys in Kozár and Konczné Benedicty (2007) and Caballero & Ramos-Portilla (2018) . 1. Circulus present; antenna 5 segmented.................................................................... 2 - Circulus absent; antenna 6 segmented..................................................................... 3 2. Body setae clavate; anal ring setae flagellate; with 2 circuli................................................ baskyi - Body setae flagellate; anal ring setae clavate; with 1 circulus............................................. epicopus 3. Multilocular disc pores present; body setae clavate, elongate, dilated only at tip; anal ring setae numbering 6–17..... coffeae - Multilocular disc pores absent; body setae clavate to falcate, short, stout throughout length; anal ring setae numbering 18....................................................................................... udzungwensis sp. n.