First-instar tergal chaetotaxy of Campylothorax sabanus First-instar and adult C. sabanus described below were collected in Puerto Rico, Isabela, Guajataca Commonwealth Forest, leaf litter on summit of mogote at intersection of trails 25, 26 and 27, 3 January 2014, F. Soto and H. Soto, two first instar and two adults. Additional observations on adult C. sabanus morphology are based on material collected at Puerto Rico, Mayagüez, Cerro Las Mesas, leaf litter along road, 23 October 1997, F. Soto, one specimen; Maricao, Monte del Estado Commonwealth Forest, leaf litter near observation tower on Rd. 120, 8 June 1998, F. Soto, two specimens; Utuado, Rio Abajo Commonwealth Forest, leaf litter on summit of mogote 10 January 2014, F. Soto, two specimens. US Virgin Islands, St. Thomas, patch of forest along Rd. 40, 20 June 2000, F. Soto, one specimen; St. John, Cinnamon trail, 30 June 2000, F. Soto, two specimens. Determination of primary chaetotaxy homology for C. sabanus is based on comparisons with the chaetotaxy reported in the literature for Trogolaphysa jataca (Wray, 1953) (Soto- Adames 2015), Pseudosinella decipiens Denis, 1924 and P. impedens Gisin & Gama, 1969 (Barra 1975), Seira dowlingi (Wray, 1953) (Soto-Adames 2008), Homidia jordanai Pan, Shi and Zhang 2011, Orchesella fl avescens (Bourlet, 1839), Heteromurus nitidus (Templeton, 1836), Entomobryoides purpurascens (Packard, 1873), Willowsia buskii (Lubbock, 1870), Pseudosinella alba (Packard, 1873) and Cyphoderus albinus Nicolet, 1842 (Szeptycki 1979). Three specimens that are as large as the two first-instar specimens described below carry secondary scales and already have the reduced number of elements present in adults. Thus, Campylothorax is similar to Trogolaphysa in that the transformation and reorganisation of the chaetotaxy take place abruptly in the second-instar nymph, rather than the gradual change observed in Entomobryidae (Soto-Adames 2015). Head First-instar C. sabanus carries the eight rows of chaetae typically found in Entomobryoidea ...