Lachesilla foreli n. sp. Female

(Figs 27–30)

Diagnosis. Subgenital plate posteriorly straight, flap broad, concave proximally, nearly circular. Gonapophyses stout, sides parallel, distally straight; ninth sternum broadly pentagonal, unpigmented, except for the antero-lateral borders.

Description. Color (29 years in 80% ethanol). Body chestnut brown, compound eyes black, ocelli hyaline, with ochre centripetal crescents. Maxillary palps reddish brown. Antennae and legs pale brown. Wings hyaline, veins pale brown, R1 bordering pterostigma ochre. Abdomen whitish, with brown subcuticular rings faded ventrally.

Morphology. As in diagnosis, plus the following: Compound eyes below the level of the slightly emarginate vertex. Forewing pterostigma long, wider distally, Rs-M fused for a short distance, areola postica low, rounded apically, broadly triangular (Fig. 27). Subgenital plate (Fig. 29) wide, setose, with pigmented area anteriorly concave in the middle. Gonapophyses and ninth sternum (Fig. 28), spermapore small, with a pigmented rim, located slightly anteriorly. Paraprocts (Fig. 30) almost semi-circular, setae as illustrated, sensory fields with 11 trichobothria. Epiproct (Fig. 30) wide, slightly concave anteriorly, rounded posteriorly, with field of setae as illustrated.

Measurements. FW: 2105, HW: 1586, F: 381, T: 697, t1: 221, t2: 64, ctt1: 12, Mx4: 99, f1: 208, f2: 155, f3: 136, f4: 116, f5: 66, IO: 325, D: 155, d: 93, IO/d: 3.49, PO: 0.60.

Specimen studied. Holotype female. MEXICO . Oaxaca . Km 168, Hwy. Oaxaca City-Puerto Angel. 30.i.1988. Beating vegetation. E. Barrera, A. Cadena & E. Ramírez (CNIN).

Etymology. This species is dedicated, in memoriam, to Auguste Forel, author of the Insecta. Hymenoptera . Formicidae . Volume III (1899–1900), of the Biologia Centrali-Americana.

Remarks. As well as L. querpina García Aldrete (1991), from the Mexican states of Durango, Guerrero, Morelos, Nuevo León and Oaxaca, L. foreli n. sp., has the flap of the subgenital plate short and rounded, almost semi-circular; in the former species the posterior border of the subgenital plate is rounded, and the gonapophyses and ninth sternum are quite different in both species (see García Aldrete, 1991).