Eurycotis improcera Rehn

Lu, Wenhua, Valentine, Barry D., Perez-Gelabert, Daniel E. & Gutiérrez, Esteban, 2014, Ecology and Diversity of Cockroaches (Dictyoptera: Blattaria) from the Virgin Islands, Insecta Mundi 2014 (349), pp. 1-32 : 22

21. Eurycotis improcera Rehn ( Fig. 17 )

Eurycotis improcera Rehn 1930: 48 ; USVI: St. Croix.

Diagnosis. Adults 16–24 mm, brachypterous with quadrate tegmina in both sexes that barely overlap; oval, yellowish brown with dark brown pattern; dorsum shiny, tegmina densely and finely punctate; head yellowish with a distinct dark band across vertex between eyes and another across frons above clypeus, and an irregular, often weakly defined, dark area between antennal insertions; pronotum broader than long, with 2 large, elongate-oval, oblique, dark brown spots connected anteriorly, and sometimes weakly connected to a dark basal band, which does not reach lateral margins; tegmina with basal margins, suture, and transverse discal grooves variably dark brown; anteroventral margin of fore femur with a row of 13 progressively decreasing spines and 3 larger distal spines (Type A 3); basal and apical tarsomeres darker than intermediate; 4 or 5 hind tarsomeres (sometimes 4 on one leg and 5 on the other); abdomen dark brown with yellowish lateral margins, each segment slightly darker anteriorly than posteriorly; segment 7 broadly convex dorsally in female, last tergite triangular with apex broadly excavated in both sexes.

Nymphs have the same yellowish lateral margins of the abdomen but are duller and the number of segments with yellowish margins is variable, increasing with age, suggesting a random ontogenetic progression. Legs are darker in younger nymphs. The largest nymphs (~ 18 mm long) have no external indication of wing pads. An oothecum is twice as long as broad, 11 mm long, with 8 egg chambers on each side; each opening side (lip) has a submarginal, longitudinal ridge across the egg chambers, and 17 small, marginal teeth.

Comments. Eurycotis improcera is a common species on Guana Island and probably arboreal and nocturnal; individuals were active at night on tree branches at> 2 m high, never under ground cover, but were caught in pitfall traps, probably during dispersal ( Table 1). The sex ratio is about 1:1. Nymphs can be sorted according to head width categories of 2.0, 3.5, 4.0, 5.0–5.5, 6.5–7.0, 7.5–8.0, and 8.5–9.0 mm (adult 9.0– 11 mm), suggesting seven instars. We observed active females carrying oothecae at night in Octobers of 2007, 2008, and 2009.

Originally described from St. Croix, Eurycotis improcera has three congeners from Puerto Rico ( Gutiérrez 2004): E. decipiens (Kirby) , E. gurneyi Gutiérrez , and E. victori Gutiérrez. The misidentification of E. improcera as E. decipiens from Guana Island ( Lazell 2005) suggests morphological similarity of the two. It is herein recorded for the first time on St. John of USVI, Great Camanoe, Jost Van Dyke, Little Thatch, Moskito, Tortola, and Virgin Gorda of BVI, in addition to another previous record on St. Croix ( Princis 1966).

Specimens examined. AMNH — 1 male, USVI, St. John , Virgin Island National Park, 19-27. VII.1972, A. Gray. BDVC —1 nymph, BVI, Great Camanoe Is., 20.X.2008, S. C. Valentine-Cooper ; 1 male, BVI, Guana Is. , 22.X.2000, B. & B. Valentine ; 1 male, BVI, Guana Is., N shore, 17-23.X.2007, B. D. Valentine family ; 1 male, BVI, Guana Is. , White Beach, 15.X.2007, W. Lu ; 1 female [with oothecum], BVI, Guana Is. , Pyramid, 22.X.2007, B. D. Valentine family, sweep ; 1 female, BVI, Guana Is. , 8.X.2004, B. D. & S. C. Valentine-Cooper, at UV ; 1 female, BVI, Guana Is. , 17-23.X.2000, B. & B. Valentine ; 1 female, BVI, Guana Is. , Palm Ghut, 18.X.2007, B. D. Valentine family ; 4 female nymphs, BVI, Guana Is. , Quail Dove Ghut, 9.VI-9. VII.2000, V / VIII.2003, VII.2006, W.-P. Liao, Malaise trap ; 1 nymph, BVI, Guana Is., 16-22.X.2002, B. D. Valentine ; 1 nymph, BVI, Guana Is., 5-19.X.2005, B. D. & B. S. Valentine ; 2 nymphs, BVI, Guana Is., 16.X.2007, W. Lu ; 1 nymph, BVI, Guana Is., 2.X.2009, D. M. Dennis & W. Lu ; 1 female, BVI, Jost Van Dyke [as Pyke] Is., 19.X.2008, W. Lu ; 1 female, BVI, Little Thatch Is. , 25.X.2008, Valentine-Cooper & Lu ; 1 adult, BVI, Little Thatch Is. , 11.X.2010, E. Wright ; 1 nymph, BVI, Moskito Is., 23.X.2012, E. Hill ; 2 males, BVI, Tortola Is. , Sage Mt., 750 m, 24.X.2002, B. & B. Valentine, beat ; 1 female / 1 male, BVI, Tortola Is. , Chalwell, XI.2002 / IV.2011, C. Petrovic, at light ; 2 nymphs, BVI, Tortola Is. , Sage Mt., 15.X.1999 / 28.X.2006, W. Lu ; 1 nymph, BVI, Tortola Is. , Sage Mt., 22/ 28.X.2009, S. Valentine-Cooper ; 1 male, BVI, Virgin Gorda Is., SW coast, 14.X.2004, B. S. Valentine, at UV ; 1 male nymph, BVI, Virgin Gorda Is. , Oil Nut Bay, 12.X.2008, [B. S. Barker]. MCZ — 2 adults, BVI, Guana Is., B. & B. Valentine. NMNH — 2 males / 1 female, BVI, Guana Is., hotel area, 6-13.X.2001, D. E. Perez-Gelabert ; 1 female, BVI, Guana Is. , Quail Dove Ghut, I.2003, W.-P. Liao, Malaise trap ; 1 male, BVI, Guana Is. , 9.X.2002, W. Lu. UDCC — 1 male, BVI, Guana Is., 8.X.1994, C. R. Bartlett .

Figures

Figures 17–20. Blattidae. 17) Eurycotis improcera adult from Guana Island. 18) Eurycotis sp. 1 adult from Tortola Island. 19) Periplaneta americana adult from Guana Island. 20) Periplaneta australasiae adult from Guana Island (all specimens in BDVC).