Identification of second instar larvae of Panchaetothripinae (Thysanoptera Thripidae) in Brazil and Argentina Author Lima, Élison Fabrício B. Universidade Federal do Piauí, Campus Amílcar Ferreira Sobral, Coleção de História Natural da UFPI. BR 343, Km 3.5. Floriano, PI, Brazil. 64808 - 605. Author O’Donnell, Cheryle A. United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine, Plant Health Programs, National Identification Services. 10300 Baltimore Avenue, Beltlsville, MD, USA. 20705. Author Sousa, Yago Lucas C. Universidade Federal do Piauí, Campus Amílcar Ferreira Sobral, Coleção de História Natural da UFPI. BR 343, Km 3.5. Floriano, PI, Brazil. 64808 - 605. Author Zamar, María Inés Instituto de Biología de la Altura, Universidad Nacional de Jujuy. Avenida Bolivia 1661, San Salvador de Jujuy, Argentina. 4600. text Zootaxa 2021 2021-10-01 5047 4 453 464 journal article 10.11646/zootaxa.5047.4.5 1175-5326 5543069 AEE40945-007F-431F-AC14-820B915DF906 Key to second instar larvae of Panchaetothripinae in Brazil and Argentina 1. Abdominal segment X with 16–18 anal setae ( Fig. 41 ).......................................... Retithrips syriacus -. Abdominal segment X with six anal setae ( Figs 35, 36, 42 ).................................................... 2 2. Major dorsal setae clavate, fringed or expanded distally....................................................... 3 -. Major dorsal setae more slender, acute or blunt.............................................................. 9 3. Dorsal setae strongly expanded distally (maximum width of setae at least 3x wider than at the base) ( Figs 15 , 20 )......... 4 -. Dorsal setae with apex different (if expanded, not remarkably broad)............................................ 5 4. Dorsal setae with concave (crateriform) apex ( Fig. 20 ); head with setae D1 inserted posteriorly to D4 setae, D3 with apex expanded......................................................................... Parthenothrips dracaenae -. Dorsal setae with convex apex ( Fig. 15 ); head with setae D1 inserted anteriorly to D4 setae, D3 with apex acute............................................................................................. Bradinothrips musae 5. Abdominal segments IX and X brown, completely sclerotized ( Figs 36, 37 ) ( Dinurothrips )........................... 6 -. Abdominal segments IX and X clearer, not fully sclerotized ( Figs 38, 39 )........................................ 7 6. Abdominal segments IX 0.7–0.8x longer than wide; abdominal segment X 1.4–1.5x longer than basal width; posterior margin of segment X with teeth medially only, between D1 setae..................................... Dinurothrips hookeri -. Abdominal segments IX 0.6x longer than wide; abdominal segment X 1.1–1.3x longer than basal width ( Fig. 37 ); posterior margin of segment X with minute teeth laterally only................................................ D. vezenyii 7. Dorsal setae emerging from tubercles and with weakly expanded apex (about 1.5x wider than basal quarter) ( Fig. 39 ).......................................................................................... Helionothrips errans -. Dorsal setae not emerging from tubercles and with apex about 2x wider than basal quarter ( Caliothrips )................ 8 8. Setae on meso- and metanotum short, about 4x longer than setae basal width; apex strongly expanded, at least 3x wider than basal quarter width ( Fig. 22 )................................................................................................................................................................ Caliothrips phaseoli -. Setae on meso- and metanotum, more than 10x longer than setae basal width; apex less expanded, 2x wider than basal quarter width ( Fig. 21 )....................................................................... Caliothrips insularis 9. Setae on antennal segment III longer than the segment length ( Fig. 6 )............................................................................................................................ Brachyurothrips anomalus -. Setae on antennal segment III as long as or shorter than the segment length ( Figs 7–14 )............................. 10