Lactista eustatia n. sp. is described from St. Eustatius, West Indies. This is the first record of the genus in the West Indies.
Introduction
The genus Lactista Saussure includes eight species distributed from southwestern US through lowland Mexico and Central America to Venezuela. The genus in Mexico was treated by Hebard (1932) and later reviewed and revised by Otte (1984). It had not been recorded from the West Indies. Individuals occur on disturbed or eroded ground and occasionally beaches. Orthopterans collected by A. C. J. Burgers on St. Eustatius, West Indies, were provided by the Zoölogisch Museum, Amsterdam. A review of specimens revealed a new species of Lactista.
St. Eustatius, Saba, and St. Maarten comprise the northern part of the Netherlands Antilles. St. Eustatius, about 243 km east of Puerto Rico, is 30 km2 (ca. 8 km long, 3.7 km wide). The trade winds are predominantly easterly and monthly mean temperatures range from 24°C to 27°C in the central region. Precipitation is very erratic but mean values range from 37 mm (Mar) to 165 mm (Sept) on the elevated central plain. Annual precipitation reaches 1500–2000 mm on the high slopes of a volcanic crater. A short beach is on the west side of the island and hills occupy the northern third. Vegetation on the plain, coastal area, and northern hills is a subtropical dry forest scrub consisting of sparse to dense grass, a variety of shrubs, and scattered small trees. The vegetation changes to a subtropical moist forest on the upper slopes of the crater (Stoffers 1956).
Lactista eustatia n. sp.
Diagnosis.
Table 1Table 1 shows morphological characteristics of Lactista species. The major diagnostic characteristic is the incomplete peripheral dark band on the hindwing that curves outwardly from the middle of the posterior margin one half to two thirds of the distance to the anterior margin (Fig. 4). All other Lactista species have a complete band except L. humilis, where the band may be slightly interrupted near the anterior margin. The combination of a weakly angulate or (rarely) rounded lateral lobe with a weak or absent apical projection, separates L. eustatia from all species except L. micrus. The angle of the pronotal posterior margin is 90° or more, which separates L. eustatia from all species except L. humilis and L. micrus. The latter two species are further differentiated from L. eustatia by 1) the position and width of the hindwing band along the posterior margin, i.e., it extends only slightly, rather than extensively, along the posterior margin and is relatively narrow, rather than broad, in the two species (cf. Otte 1984); and by 2) the pale translucent blue or green color of the hindwings, rather than the translucent yellow of L. eustatia n. sp.
Description.
Specimens were stored in alcohol by the collector which caused slight to moderate shrinking of some surfaces, likely some loss of body color, and a slight loss of color in the basal portion of the hindwings.
Males: Head (Fig. 1): antennae ca 6.5 mm long, 22-segmented flagellum, distal half darker than proximal half; upper end of frontal ridge below fastigium and elongated region below central ocellus depressed, lateral margins incurved between ocellus and upper depression and strongly incurved immediately below ocellus; lateral foveolae broad-oval, concave; fastigium produced anteriorly, strongly depressed between compound eyes, high lateral margins adjacent to eyes; vertex rugose, usually with broadly oval depressed region each side of weak or obsolete median carina.
Thorax (Figs 2,3): median carina of pronotum elevated, weakly arched, sometimes sinuous in prozona, cut deeply by one sulcus; dorsal and dorsolateral areas of prozona rugose from large flattish, bluntly pointed, or ridged nodules, raised aggregation of nodules each side of median carina near sulcus, aggregation may form a raised platform in an irregular triangular shape, raised triangle sometimes opaque; metazona with scattered small nodules dorsally, median carina moderately elevated, distinct lateral carinae absent, sometimes replaced with low irregular ridge; metazona posterior margin bluntly pointed, slightly greater than 90°; lower posterior margins of lateral lobes weakly angulate, usually incurved subapically, roundly pointed apex.
Legs: outer and inner margins of front and middle tibiae each with 3 to 4 black-tipped spines, 4 black-tipped subapical spines; outer margin hind tibia with 9 to 12 black-tipped spines, inner margin with 7 to 8, 2 pairs at apex; hind femora with two pale and two black bands on inner and ventral margins, proximal band longer.
Wings (Fig. 4): tegmina 6.4 times longer than greatest width, 2 to 3 brown transverse bands, third (distal) band fainter and elongated laterally, distal fifth of tegmina may be dull-whitish opaque; intercalary vein with ca 55 faint nodules per mm; hindwing faintly suffused with very pale yellow in basal half, dark brown to blackish peripheral, incomplete band curving outwardly from middle of posterior margin one half to two thirds distance to anterior margin; laterally elongated, slender dark band centered slightly distal to middle of anterior margin, extending from anterior margin to second (discoidal) vein.
Abdomen: base of epiproct expanded into three slightly concave quadrate regions, distal margins bowed and elevated, distal region epiproct broadly triangular, area between longitudinal ridge and lateral margin slightly concave, lateral margin curved up proximally; paraprocts lateroventrally concave, extending to or slightly beyond apex of epiproct; subgenital plate broadly triangular, broadly rounded apex slightly projecting; cerci elongate triangular, outer surface slightly concave.
Females: like males but larger; tegmina 5.5 to 6.3 times longer than greatest width.
Coloration and color variation.
Overall color brownish tan, varying from light tan to brown; tegmina and wings as previously described.
Paratypes.
(1 ♂ and 6 ♀ ♀) 3 ♀ ♀, St. Eustatius, near Oranjestad, 21-Feb-1949, A.C.J. Burgers; 1 ♂, 3 ♀ ♀, St. Eustatius, near Concordia, 21-Feb-1949, A.C.J. Burgers.
Acknowledgments
Willem Hogenes (Zoölogisch Museum, Amsterdam, The Netherlands) kindly provided the collection for review. Daniel Otte (Academy of Natural Sciences, Philadelphia) confirmed the correct genus.
References
Table 1.
Morphological characteristics of Lactista species.
Table 1
continued.
Table 2.
Measurements (averages and ranges in mm) of L. eustatia derived from the holotype and 8 paratypes. BL = body length (head to tip of abdomen, including ovipositor); HF = hind femur length; ID = interocular distance; PL = pronotum length; TL = tegmen length; TW = tegmen width (maximum).
