(Fig. 143–145, 249)

Holotype male (dissected), Costa Rica, labeled: “ COSTA RICA, Prov. Alajuela, San/ Ramón, Est Res Biol Alberto Brenes,/ R. San Lorencito. 850m. 19–26 MAR/ 1999. J. Rodrígez. Manual (red, libre)/ L N 245500 470800 #52440”, INB0003053835 (INBC).

Paratypes 42 (23 males, 19 females), Costa Rica and Panama, labeled: “ Rio Sn Lorencito, 900m / Res. For. Sn Ramon, 5 km N/ Col. Palmarena, Alajuela / COSTA RICA. Mar 1990 / Curso Carabidae / 244500­4707000”, CRI000 159859 (INBC); “ COSTA RICA, Alajuela: R. B./ A. Brenes, Rio San Lorencito,/ 900m, 10°13'N 84°36'W,/ 4.–6.iv.2003, leg. J. Prena ” (JPPC); “Orozi/ Costarica”, “1912/ 18”, “Staatl. Museum für/ Tierkunde Dresden” (SNSD); “Costa Rica, CARTAGO:/ 17 km SE Cartago, P.N./ Tapantí, 1200 m,/ 7/ 8.4.2000, leg. Prena ” (JPPC); “ COSTA RICA, Limón: Hitoy/ Cerere Biol. Res., Valle de la/ Estrella, 300m, 21.–29.i.1996,/ leg. J. Prena ” (JPPC); “Est. Hitoy Cerere, 100m,/ R. Cerere, Res. Biol. Hitoy/ Cerere, Prov. Limon,/ COSTA RICA, G. Garballo / 6–25 Nov 1991,/ L­N­184200, 643300”, CRI000 498875 (INBC); “ COSTA RICA / Pr. Heredia/ Puerto Viejo/ Finca La Selva ”, “ R.J. Marquis coll./ No. 936 8­V­1982 ”, “ Piper / imperiale” (NMNH); “ COSTA RICA: Prov. Heredia:/ 10km SE La Virgen, 450–/ 550m, 10°20'N 84°05'W / 1.3.2000 / INBio­OET­ALAS transect”, “handcollecting/ leg. Jens Prena ”, without barcode (JPPC 4); same label except 17.– 23.2.2003, INB0003229807–11 (INBC 5), 11.– 16.3.2003, INB0003229889–91 (INBC 3), 17.– 20.3.2003, INB0003229967–71 (JPPC 5), 8.– 13.4.2003, INB0003230057–65 (CWOB 2, JPPC 7), 14.– 20.4.2003, INB0003230149–51 (CHAH, INBC 2); “ COSTA RICA, Prov. Heredia:/ 12km SE La Virgen, 550–/ 650m, 10°19'N 84°05'W / Prena, 15.III.2001 / INBio­OET­ALAS transect”, INB0003210004 (JPPC); “ COSTA RICA: Prov. Heredia:/ 13km SE La Virgen, 650–/ 750m, 10°18'N 84°05'W / 22.2.2003 / INBio­OET­ALAS transect”, “handcollecting/ leg. Jens Prena ”, INB0003229862 (INBC); “ COSTA RICA, Prov. Heredia:/ 16km SSE La Virgen, 1050–/ 1150m, 10°16'N 84°05'W / 10.–14.III.2001 / INBio­OET­ALAS transect”, “handcollecting/ leg. Jens Prena ”, INB0003209857 (JPPC); same label except 10.– 14.IV.2001, INB0003209942 (INBC); “ PANAMA: Cocle Prv./ La Mesa ab. El Valle/ Cerro Caracoral/ 15 Nov 92; el. 800 m / col. H. Stockwell ” (HPSC, JPPC).

Description. Habitus: Fig. 143, total length 4.9–6.5 mm (m=5.7, n=22). Color: integument rufous­castaneous, venter piceous; basic vestiture moderately dense, cupreous, with few clusters of light yellow scales, dorsolateral pronotal vitta indistinct, scales velvety black in variously shaped, oblique elytral macula between interstriae (1)2–5, usually separated from each other by sutural interstriae (Fig. 143a, b); venter with white scales on prosternum and along flank. Head: frontal fovea absent, rostrum rather slender, subcylindrical (Fig. 144), apex slightly expanded laterally, subcostate dorsomedially, basolateral margin slightly edged, length of rostrum ♂♂ 0.97–1.12 x (m=1.06, n=13), ♀♀ 1.06–1.19 x (m=1.14, n=9) pronotal length, length of ante­antennal portion ♂♂ 0.36–0.41 x (m=0.39, n=13), ♀♀ 0.42–0.44 x (m=0.43, n=9) total rostral length, dorsal margin of antennal scrobe reaching rostral base before eye; funicular segment 2 slightly longer than 1, club oblong ovate. Pronotum: length 0.95–1.02 x (m=0.99, n=22) maximum width, sides rounded, widest in basal half, anterior portion tubulate; disk densely punctate, intervals granulose, subcostate dorsomedially or not. Elytra: length 1.75–1.89 x (m=1.83, n=22) width at humeri, width 1.21–1.35 x (m=1.28, n=22) maximum pronotal width, sides subparallel in basal half, apices rounded conjointly, preapical callus developed, striae fine, punctures indistinct, interstriae flat, 9 costate, 7 subcostate near subapical callus. Legs: slender, tibia nearly straight and parallel­sided, ventral margin with distal cluster of cupreous hairs, tarsal claws flat and approximate at base. Male: aedeagus with anterolateral membranous portion variously developed, apex round to notched, middle sclerotized (Fig. 145, or as Fig. 147), body of aedeagus of moderate size, curved in lateral view, apodemes 2.3 x longer than body of aedeagus, flagellum thin, longer than apodemes, transition to curved base gradual, basal appendage elongate, slightly curved, fused subdistally with base of flagellum, projecting far beyond base (as Fig. 148).

Plant association. Species of Piper with the shoot­apex emerging from within the leafbase at flowering nodes: P. euryphyllum (Prena 24), P. imperiale (Marquis 1, Prena 5), P. biseriatum (Prena 2), P. cenocladum (Prena 1), P. obliquum (Prena 1).

Distribution. Costa Rica, Atlantic side and central Panama (Fig. 249).

Specific epithet. The name is a Greek compound noun (chasma = cleft, rip).

Discussion. Embates euchasma forms a complex with E. subulirostris, E. cordiger and E. oculifer. The distribution of E. euchasma and E. cordiger overlaps in Atlantic Costa Rica (Fig. 249, 258), where E. euchasma occurs primarily on Piper euryphyllum and E. cordiger on P. cenocladum. Both species differ in body size, shape of tarsal claws and color­pattern.