Rev. Biol. Trop. 36 (2B): 45 7-469, 1988.

Gigantodax bierigi & G. willei (Diptera: Simuliidae), two new black from Costa Rica

Mario Vargas V. Centro de Investigación y Diagnóstico en Parasitología, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, Costa Rica. Jaime Ramírez Pérez Instituto de Biomedicina, P. O. Box 4043, Caracas, Venezuela.

(Rec. 15 -IV-1988. Acep. 28-VI-1988)

Abstract: The female, male, pupa and of bierigi, new species, and Gigantodax willei, new species, are described. Each of these species is most readi1y differentiated from other species of Gigantodax, by the general shape and number of the branches of the respiratory oIgan of the pupa. Both species were collected from upland streams in Costa Rica. Sorne biological notes are inc1uded.

The Gigantodax has been reported concolorous with frons slightly lighter at from (), Bolivia, Perú, center, rather densely covered with moderately Colombia, Venezuela, Guatemala and Méxi­ short, ventromedially directed, yellow pile. co (Wygodzinsky 1949), and there are many Occiput whitish pollinose, densely �overed problems in its . The only list of with long, pale yellow pile. Antenna with nine species available is from Vulcano (1967), flagellomeres, pale brown, scape, and pedicel to which must be added, the species described concolorous with flagellum, each segment by Wygodzinsky (1973), Ramírez-Pérez (1980), paler at base, first flagellomere longer than Moncada et al. (1981) and Takaoka et al. pedicel, remaining flagellomeres subequal in (1988) for Ecuador. length fine pubescence whitish, pedicel and Wygodzinsky and Coscarón (1973) are in scape with long black setae. Mandible (Fig. process of describing several new species l-B) with about 17-23 serrations. Blade of which will help to better define the genus. maxilla (Fig. l-H) with about 9-14 retrorse Gigantodax bierigi Vargas and Ramírez-Pérez, teeth. Palpus (Fig. l-K) dark brown, all palpo­ new species. meres similar, with long brown setae. Palpome­ Female (dry, pinned specimens). General re five slightly longer than three, proportion body color blackish brown. Length: body, of palpomeres 1:0.8:3.3:3:4. Sensory vesic1e 3.0 mm; wing, 3.5 mm. as in (Fig. l-D), about 1/2 as long as its segment, Head: Blackish, with whitish pollinosity. proximally situated, its neck long, arising Frons (Fig. loA) narrow, near1y parallel sided, anterodorsally and extending vertically. with only slightly widening dorsally, about three an enlarged mouth. Median proximal space times longer than width, about 1/6 width of of cibarium shallow, without dentic1es; dorso­ head; slightly paler than occiput, rather densely lateral arms short, weak1y sclerotized; inner covered with moderately long, decumbent, surface of each arm smooth, without 'llinute yellow pile. Postocular setae brownish. Clypeus setulae.

457 458 REVISTA DE BIOLOGIA TROPICAL

r 0.02 B

Hg. 1. Gigantodax bierigi n. sp. A. Frons of female, B. Apical regíon of mandible, C. spermatheca. D. sensory vesicle of maxíllary palpus. E. cercus and anal lobeo F. ventral plate in ventral view, G. wing showing portio n of C, Rl and J, K. Rs' H, apical regio n of blade of maxílla. I. gonostylus. genital fork. maxíllary palpus. VARGAS & RAMIREZ: Gigantodax bierigi & G. willei, two new species 459

Thorax: B1ackish brown; antepronotal lobe spicules; with a corrugated area at junction conco1orous with scutum, with moderately with the spermathecal duct. dense, long yellow pile. Postpronotum b1ack, smooth. Scutum black, with a sparse nacreous MaJe: (dry, pinned specimen). General body pollinosity and covered by an abundant long color blackish-brown. Lenght; body, 2.5 yellowish pilosity. Scutellum paler than mm; wing, 3.7-3.8 mm. scutum; densely covered with long, golden setae on hind margino Postnotum black with Head: F,rons and clypeus black, nacreous a few short yellow setae and abundant pollinose, with erectt yellowish pile. Occiput nacreous pollinosity. with short, yellow setae. Antenna dark brown; Anterior half of p1euron black, concolorous scape and pedicel yellowish, remaining flagello­ with the posterior half. Presternal lobe dark meres becoming darker distally; first flagello­ brown with yellowish pile. Anepisternal mere slight1y broadened distally, slightly membrane darker than rest of pleuron, with longer than pedicel, fine pubescence mixed whitish pollinosity. Mesepimeral tuft light with black setae; pedicel with long setae brown. Wing (Fig. l-G) membrane hyaline, laterally and distally; scape with long, black with a lig.1tt brownish tinge; veins yellowish setae at distal angle. Palpus brown, proximal brown. Base of C and stem vein with long two and distal two palpomeres paler than third, black pile, rest of setae on veins black. Sc and with black pile interspersed with a few setose ventrally, R setose dorsally, R4+5 more yellowish setae; palpomere five about setose ventral1y; cell bm absent; C. with 1/4 longer than palpomere three and about spiniform setae; fringe of calypter and alar 1/3 longer than palpomere four. Sensory lobe long and yellow. Stem of halter brown­ vesicle round, 1/4 as long as its segment; ish, knob whitish, with hairs at base. Legs neck short. rather uniformly light brown, except for dark apex of femur and basal and distal areas Thorax: Antepronotum and póstpronotum of tibiae; coxae 1 and 11 with only dark setae, concolorous with scutum; antepronotum with hindcoxae with paler setae, rest of setae on yellow setae; postpronotum bare. Scutum 1egs light brown. Hind basitarsus about eight dark brown, densely covered with short, times as long as broad. Calcipala 1arge, broadly decumbent, pale yellow pile, and nacreous rounded. Pedisulcus absent. Claw slightly pollinose. Scutellum black, with long, yellow curving from base, with a prominent, subtrian­ setae on hind margino Postnotum concolorous guIar basal tooth that is wider than claw and with scutellum and having nacreous reflections, less than half as long as claw. Pleuron uniformily dark, nacreous pollinose. Anepistemal membrane black, bare. Mese­ Abdomen: Brownish. Basal scale (tergite one) pimeral tuft yellowish. Wing membrane hyaline dark brown, with a fringe of long, pale yellow but with a distinct brownish tinge; veins pile; tergites broad, brownish. with darker yellowish brown; base of C and stem vein brown margins, sparsely covered with short, with dark pile, rest of setae on veins dark; Sc pale yellow setae; pleural membrane brownish, setose ventrally; base of R and R 1 setose bare, with faint whitish pollinosity. Terminalia dorsally; R4+5 setose ventrally; C and distal as in Fig. 1 (C, E. J). Anal lobe subquadrate, half of R 1 with spiniform setae that are with a notch posteroventrally; moderately shorter than regular setae; cell bm absent; covered with stout light brown setae. Cercus fringe of calypter and alar lobe pale yellow. sub rectangular, with abundant light brown Halter brownish, knob bare. Legs rather uni­ setae. Hypogynial valves very small, not reach­ formüy light brown, with color pattern as in ing base of cerci. Stem of genital fork (stemite female, with light brownish pile; hind nine) long, slender and moderately sclerotised, basitarsus not swollen, about 6.6 times as about half long as arms; arms short, weakly long as broad; calcipala large, distinct, rounded sclerotised except for a short, heavily sclero­ apically; pedisulcus absent. tised rod-like extension (lateral process) on each side emanating from stem of genital Abdomen: Blackish, basal scale light brown, fork. Spermatheca ovoid, without reticulate with abundant long brown setae along hind pattem, but with sparse minute internal margino Tergites narrow, sparsely covered with 46 0 REVISTA DE BIOLOGIA TROPICAL

B

\ -+----

F

Fig. 2. Gigantodax bierigi n. sp. A, respiratoryorgan of pupa. B. larval antenna. C. larval hypostoma. D, pupal frons. E, apical regio n of larval mandible. F. abdomen of pupa. G. larval hypostomal cleft. VARGAS & RAMIREZ: Gigantodax bierigi & G. willei, two new species 461 long, yellowish setae. Sternites brownish. excavation extending about 2/8 distance to Terminalia as in Fig. 1 (1, F) Gonocoxite base of hypostoma. Hypostomal bridge trapezoidal, covered with short black setae distinct1y longer (35 :24) than hypostoma. and long píleo Gonostylus subtriangular, Mandible (Fig. 2-E) with an apical tooth, 2 elongated, notched at basal angle, setose, external, 1-3 preapical and 7-13 inner teeth; apical margin bearing two, large terminal inner subapical ridge with about 7-15 fme spines. Body of ventral plate of aedeagus serrations. Maxillary palpus about 2.8 times ovate, elongated, moderately sc1erotized, as long as width at base. Lateral plate of proleg densely covered with light setae; distal margin extending half length of apical segment; rounded, keel-like lobe or ventral flap well­ irregularly subtriangular, two times longer than developed, half-heart shaped overeaching lateral width; lightly sc1erotized and with about 36 margin of plate, covered with short setae; setulae projecting distally toward bases of basal arms sc1erotized, an inverted V-shape, hooks; circ1et of apical hooks arranged in slight1y shorter than length of body of ventral about 44-47 rows with 11-12 hooks each. plate; median sc1erite of aedeagus short, stem Basal area of anal sc1erite with short well­ larger than arms; aedeagal membrane rather sc1erotised, basal wings with 4+4 anal scales densely covered with numerous rows and of 2, 3 or 4 prongs situated near auxiliary groups of 4-5 minute setulae. PI ate of strut-like structures and about 20 additional endoparameral organ membranous, poor1y anal scales in a circ1et near anterior wings which sc1erotized, with one big fusiform and a group have a serrated anterior border; rectal gills of about seven small spines, arm moderately three, digitiform. Posterior circ1et of hooks, long, sc1erotized and twisting. consisting of about 25 hooks in about 108- 120 rows. Larva (Mature, with fully developed respiratory histoblasts) Length about 7.0 mm . General Pupa. Length about 4.0 mm. Respiratory body color brownish; intersegmental line organ (Fig. 2-A) about 2.7 mm . long, consisting narrow, lighter than rest of abdomen. Head of five main basal fIlamentous corrugated capsule dark; head spots darker than surround­ trunks, branching as follows: one long, single ing area, anteromedian and posteriomedian posteroventral branch, two long dorsomedial spots slender, elongate, well separated; first and two short anteroventral branches, latter and second anterolateral spots roundish, about two groups variably bearing shorter accesory equal in size and distinct1y separated; postero­ branches. Head (Fig. 2-D) and thoracic integu­ lateral spots darkened. Eye spots small. ment with round and ovoid granulosities Postocciput with a broad gap dorsally, cervical that are darker than rest of integument. An­ sc1erites slender, well defined and fused at tenna of male reaching 3/4 distance hind their bases with the lateral areas of the head. margin ·of head; antenna of female reaching Antenna (Fig. 2-B) pale brownish, shorter than hind margin of head; a single, slender seta stalk of labral fan; proportions of segments present near inner comer of each antenna; (basal to apical) 1: 0.9: 1.7: 0.1. Labral fan each side of thorax with about one antero­ with 25-29 (mean 27) primary rays. Hypostoma dorsal, two mediodorsal, one posterodorsal, as in Fig. 2-C; with 17 teeth arranged in three two medioventral, and one posteroventral main groups of 7+ 1 + 7 plus a small tooth on long, single, trichomes; anterodorsal trichomes each side at base of median tooth; median stoutest. Dorsal abdominal chaetotaxy as follows tooth long, subequal to longest lateral tooth (Fig. 2-F): Segment 1 with 5+5 fine setae; of each side; each lateral group of teeth varying II with 8+8 spines; III with 4+4 hooks and in structure to median group, consisting of 4+4 spines; IV with 4+4 hooks and 4+4 spines; (from inner to outer): small, median, large, V with 4+4 fine setae; VI with a row of scales median, median, small and large teeth, outer and 3+3 fine setae; VII with a row of scales lateral margins of hypostoma with about 15 and 2+2 fine setae, VIII with a row of scales dentic1es irregularily distributed; six or seven and 2+2 spines; IX bare. Ventrally: Segment long lateral setae and two large hipostomal III with 1+1 setae; IV with 5+5 spines; V setae, longest seta overeaching tip of longest with 3+3 hooks, 1+1 spines and in addition hypostomal tooth. Hypostomal c1eft (Fig. 2-G) 3+3 spines on striated area, VI with 3+3 hooks poorIy defined, a shallow, rather V-shaped plus 1+1 hooks, 2+2 spines and 1+1 setae on 462 REVISTA DE BIOLOGIA TROPICAL

Fig. 3. Gigantodax willei n. sp. A, apical region of blade of maxilla. B, apical region of mandible. C, genital fork. D. frons of female. E, sensory vesicle of maxillary palpus. F, wing showing portion of C, Rl and Rs. G, maxillary palpus. H, cercus and anal lobe. 1, ventral plate in ventral view. J, gonostylus. K, spermatheca. VARGAS & RAMIREZ: Gigantodax bierigi & G. willei, two new species 463 striated area; VII with 1 + 1 hooks, 1 + 1 spines, pedicel and scape with long, black setae and 1 + 1 hooks and 2+2 spines on striated area; fine black pubescence; flagellomeres with a VIII bare; and IX with 6+6 stout spines; two few light setae and fine black pubescence. pairs of ventral plates present on segments Mandible (Fig. 3-E) with about 19-22 VI and VII, and patches of minute scales serrations. Blade of maxilla (Fig. 3-1) with present on stemites III to VIII. Cocoon about 10-12 retrorse teeth. Palpus (Fig. 3-C) sub triangular , composed of loosely woven dark 'brown, aH palpomeres similar, with threads and without a thickened anterior long brown pile and fine, light setae; palpomere margin; about 3.0 mm long. five subequal in length to three; proportions of segments: 1: 0.7 : 2.7 : 2.0 : 2.1 Sensory Types: vesic1e as in Fig. 3-G, about 1/2 as long as its segment, proximately situated, its neck Holotype, female, reared. From temporary short, with an enlarged mouth. Median stream No 73, at Rio Reventado, Prusia, proximal space of cibarium small, shaHow, Cartago, located 0.5 km NW of the "Sanatorio without dentic1es, dorsolateral arms short, Durán" on the road to Irazú Volcano, No­ weakly sc1erotized, inner surface of each vember 30, 1984. J. F. Herrera, collector arm smooth, without minute setulae. (USNM). Paratypes, same data as holotype. Thorax: Dark brown; antepronotal lobe, USNM (Mounted and alcohol specimens): concolorous with scutum, with moderately 3 females, 5 males, 3 mature and 40 immature dense long, yellow pile. Postpronotum, bare. larvae, 7 pupae and 60 empty pupal pelts. Scutum, with a few black spots, whitish U.C.R. (School of Microbiology, entomological pollinose and with abundant yellowish pile. collection. Mounted and alcohol specimens): Scutellum paler than scutum, densely covered 13 females, 4 males, 1 mature larva and 600 with long, pale yellow setae on hind margino immature larvae. 245 pupae. Postscutellum dark brown, bare. Anterior ihis species is dedicated to the late Alexander half of pleuron dark brown, concolorous Bierig, first professor of Medical with posterior half; prestemal lobe dark brown, at the School of Microbiology University of bare; anepistemal membrane concolorus with Costa Rica. rest of abdomen, but with a whitish pollinosity. Mesepimeral tuft of long, yellow hairs irregu­ Gigantodax willei Vargas and Ramírez-Pérez, lady distributed at base, and bare distally. Wing new species. (Fig. 3-D) membrane hyaline, with a light brownish tinge; veins yellowish brown; base Female (dry pinned specimens). General body of C and stem vein with short pile and long color dark brown. Length: body 3.0 mm; brown setae, rest of setae on veins brownish. wing 3.5 mm. Sc setose ventrally; R 1 setose dorsally and with spinules on distal fourth; R2+3 setose Head: Brownish; frons (Fig. 3-A) narrow, ventrally and dorsally; cell bm absent; C with nearly parallel sided, only slightly widening spines from basal 1/4 to end of vein; fringe dorsally, about seven times longer than width, of calypter and alar lobe with long, light and 1/9 width of head; paler than occiput, with brown setae. Halter light brown, with hairs yellowish pollinosity, and rather densely at base. Legs rather unifonnily light brown; covered with moderately long, decumbent coxae with a few light brown setae; hind brownish pile. Clypeus slightly lighter than basitarsus about six times as long as broad. frons; rather densely covered with moderately Calcipala large, broadly rounded. Pedisulcus short, ventromedially directed brownish pile. absent. Claw slightly curved from base, with Occiput blackish, densely covered with short, a prominent subtriangular basal tooth that yellow pile. Postocular setae yellowish, pos­ is wider than c1aw and about 1/4 as long. teriorly directed. Antenna with nine flagel­ lomeres; scape, flagellum and pedicel light Abdomen: Blackish; basal scale (tergite one) brown, except two apical flagellomeres black­ dark brown, with a fringe of long, yellow pile; ish; first flagellomeres longer than pedicel, tergites wide, with brown setae distributed remaning flagellomeres subequal in length; over surface. Pleural membrane dark brown. 464 REVISTA DE BIOLOGIA TROPICAL

0.20 e

D

E

Hg. 4. Gígantodax willeí n. sp. A, respiratory organ of pupa. B, larval hypostoma. C, pupal frons. D, apical region of larval mandible. E. larval antenna. F, abdomen of pupa. G, larval postgenal cleft. VARGAS & RAMIREZ: Gigantodax bierigi & G. willei, two new species 465

with yellowish pile. Sternites darker than brown hairs at base. Legs rather uniformily segmental membrane. Terminalia as in Fig. 3 light brown, same color pattern as females; (B, F, H). Anal lobe subtriangular with a hind basitarsus not swollen, about 6.5 times posteroventral notch; setae light and dark as long as broad; calcipala large, distinct, brown. Cercus subrectangular , with abundant rounded apically, pedisulcus absent. light brown setae. Hypogynial valves not reaching posterior border of cerci. Stem of Abdomen: Dark brown. Fringe of basal scale genital fork (sternite nine) slender, more (first tergite) yellow. Tergites narrow, dark sc1erotized and subequal in length to arms; becoming slight1y 'paler posterior1y, with arms short, hooked-shaped, weak1y sclerotized, scattered yellow setae. Pleural membrane with a rodlike extension on each side emanating light brown in anterior segments and darker from stem of genital fork. Spermatheca in posterior segments. Sternites dark, with rounded, slight1y striated, with few internal yellow setae. Terminalia as in Fig. 3 (J, K). spicules, and with a corrugated area at Gonocoxite trapezoidal with abundam long, junction with spermathecal duct. dark setae. Gonostylus subtriangular, elongated about 1/2 as long as gonocoxite, notched at Male (dry, pinned specimens). General body basal angle, with two apical spines. Body of color, dark brown. Length: body 3.0 mm; ventral plate of aedeagus ovate, with abundant wing, 3.5 mm. light hairs, distal margin with a rounded keel­ like lobeo Stem of median sc1erite of aedeagus Head. Frons and c1ypeus black, with short longer than arms; aedeagal membrane with yellowish pile. Occiput same color as scutum, abundant pale setulae. Plate of endoparameral with brown setae. Antenna light brown; pedicel organ twisted, well sc1erotized, with one big wider than first flagellomere but 1/3 as long; fusiform spine, and a group of about six small scape, pedicel and first flagellomere with light spines. brown setae and fme black pile; all flagello­ meres with a pair of hooked setae ventrally. Larva (Mature, with fully developed respirato­ Palpus light brown, second palpomere slight1y ry histoblasts). Length about 7.0 - 8.0 mm. darker than rest; all with mixture of fme black, General body color brownish; intersegmental and light brown setae; palpomere five subequal lines narrow, lighter than rest of abdomen. to third and slight1y larger than fourth. Sensory Head capsule light brown; head spots darker vesicle about 1/2 as long as its segment, with than surrounding area. anteromedian spot a wide mouth. slender and posteromedian spots rounded, both sets of spots eontiguous; three antero­ Thorax: Antepronotum and postpronotum lateral spots distinet1y separated, first smallest, dark brown, bare, concolorous with scutum. seeond median sized third largest and Scutum dark brown, eovered with abundant elongated. Eye spots of median size, black. short, yellowish pile, with narrow white lines Postoeeiput with narrow sc1erotized band; and whitish pollinosity. Scutellum lighter cervical sc1erites subtriangular, slender, fused than seutum, with long brown setae. Posts­ at their bases with lateral unsclerotized area cutellum eoneolorous with seutum, bare. of head. Antenna (Fig. 4-E) pale brownish, Pleuron dark brown; anepisternal membrane shorter than stalk of labral fan; proportions with a whitish pollinosity, bare. Mesepimeral of segment (basal to apieal) 1: 0.9:2: 02. tuft with long, yellowish hairs. Wing membrane Labral fan with 17-20 primary rays. Hy­ hyaline with a slight brownish tinge; veins postoma as in Fig. 4-B; with 17 teeth yellowish brown; base of C with long, light arranged in three main groups of 7 + 1 + 7, brown setae and abundant short setae; rest plus a small tooth on each side of base of of setae on veins light brown. Se with setae median tooth; median tooth subequal to ventrally; base of R and R 1 setose dorsally longest lateral teeth of eaeh side; eaeh lateral along entire length and with spines distally; group consisting of (from inner to outer) a R2+3 with long setae dorsally and ventrally; small, median, large, median, median, small C with spines reaehing apex; eell bm absent; and large tooth. Outer lateral margins of fringe of ealypter and alar lobe light brown. hypostoma with 5- 9 denticles irregularly Halter with brown pigment and small light distributed; with five or six long, lateral setae 466 REVISTA DE BIOLOGIA TROPICAL and two small, medial hypostomal setae and with 0-1 fme setae and 1 + 1 larger setae; two small hairs, longest seta overeaching tip IV with 5 + 5 spines and 1 + 1 spines on of longest hypostomal tooth. Hypostomal striated membrane; V with 3 + 3 hooks, 1 + ! cleft (Fig. 4-G) poorIy defmed, a shallow hooks; 3 + 3 setae on striated membrane; excavation extending about 1/8 distance to VI 2 + 2 hooks and 1 + 1 spines on striated base of hypostoma. Hypostomal bridge membrane; VII with 1 + 1 hooks, 1 + 1 spines, distinct1y longer (35: 20) than hypostoma. 1 + 1 hooks and 3 + 3 spines on striated Mandible (Fig. 4-D) with an apical tooth, 3 membrane; VIII bare; IX with 5 + 5 hooks external, 3 preapical and 7-8 inner teeth; on striated membrane. Two pairs of ventral inner subapical ridge with about 11-13 fme plates present on segments VI· and VII, and serrations. Maxillary palpus about 2 times as with patches of minute scales on segrnents long as width at base. Lateral p1ate of proleg III to VIII. Cocoon subtriangular with loose · extending ha1f length of apical segment, threads and without a thickened anterior irregularIy subtriangular, 2 times as long as bando wide; moderately sclerotized, with a circlet of numerous setulae projecting distally toward bases of hooks; circlet of apical hooks arranged Types: in about 55 rows, each with 11 hooks. Basal Holotype: female. From temporary stream area of anal sclerite with short, sclerotized No. 73, Río Reventado, Prusia, Cartago, basal wings each with a patch of numerous located 0.5 km of "Sanatorio Durán" on the scales that have 2-4 prongs near auxiliary road to Irazú Volcano, April 15, 1983. C. R. strutlike structures, and an additional circlet Méndez, collector (USNM). of anal scales, near anterior wings, each with Paratypes, same data as holotype. 1-4 prongs; rectal gills three, single, digitiforrn. USNM (mounted and alcohol specimens). Posterior circlet of hooks consisting of about 3 females, 5 males, 8 mature and 15 immature 91 rows with 19 hooks each; Anterodorsal larvae and 16 pupae. U. C. R., School oY arms less than three times as long as postero­ Microbiology, entomological collection. ventral arms. (mounted and alcohol specimens). 5 females, 5 males, 248 immature larvae and Pupa. Length about 4.0 mm. Respiratory organ 407 pupae. (Fig. 4-A) about 2.5 mm; long fllaments digitiform, consisting of five, simple, sacciform This species is dedicated to DI. Alvaro branches, with a corrugated surface, dark Wille, distinguished professor of Entomology brown in color; a clear granulosity is visible at the University of Costa Rica. over each branch. Head (Fig. 4-C) and thoracic integument with round and ovoid brownish granulosities. Antenna of male GEOGRAPHICAL DlSTRIBUTION reaching less than 3/ 4 distan ce to hind margin of head; antenna of female reaching hind From the 100 strearns in which blackflies margin of head; a single slender seta is present were collected in Costa Rica during the period near inner comer of each antenna. Each side 1968-1970 (Vargas and Travis 1973), only of thorax with about 2 anterodorsal, 1 medio­ 3 contained Gigantodax: No. 34 (Poasito, dorsal, O posterodorsal, 2 anteroventral, 1 Alajuela), No. 42 (San Juan de Chicuá, Orea­ medionventral and 1-2 long, single, postero­ muno, Cartago) and No. 73 (Río Reventado, ventral trichomes. Dorsal abdominal chaetotaxy Prusia, Cartago). During the period 1983 to (Fig. 4-F): Segrnent I with 4 + 4 setae; II 1986 stream .No. 45a (La Georgina, Pérez with 7 + 7 spines; III with 4 + 4 hooks, 3-4 Zeledón, San José) proved positive for + 3-4 spines; IV with 4 + 4 hooks, 3-4 + Gigantodax. The population densities, grossly 3-4 spines; V with 5 + 5 setae; VI with 3 + 3 estimated from numbers of larval and pupal setae and a row of scales; VII with 2 + 2 setae stages, collected during a period of one hour and a row of scales, and 1 + 1 setae on striated each month by two people, show a general membrane; VIII with 2 + 2 spines and a row pattern of low densities and the need to collect of scales; IX with 1 + 1 hooks, and 1 + 1 throughout the year, because of the scattered sclerotized processes. Ventrally: Segrnent III detection of larvae and/or pupae (Fig. 5). VARGAS & RAMIREZ: Gigantodax bierigi & G. willei, two new species 467

TABLE 1

Annual appearance ofGigantodax spp. per stream, in Costa Rica

YEAR MONTH JAN FEBR MARCH APRIL MAY JUNE JULY AUG SEPT OCT NOV DEC Stream No. 34: 1968 X X 1969 X X X X X X X X X 1970 XX XX X XX X X 1983 X X X X X X X 1986 X X XX X XX XX X X X X

Stream No. 42: 1968 X XX XX X 1969 X X XX X X X X X 1970 XX X XX X X

Stream No. 73: 1969 XXX X X X X X 1970 X X X X 1982 X XXX X X 1983 X XX X 1984 XX X X XXX XXX XXX Stream No. 45: 1983 X X X X XX XX XX 1986 XX X X XX XX XX X

X= minimum amount of larvae and/or pupae XX= moderate amount of larvae and/or pupae XXX = large amount of larvae and/or pupae

ECOLOGY a yellowish fibrous deposit on the stones that is typical of water containing sulphur. The The characteristics of the streams in which stream is partially to densely shaded by trees, Gigantodax have been collected are as follows. large shrubs and large herbaceous plants. Stream No. 34 (Poasito, Alajuela). altitude Temperature ranges from 9 to 19 C. Thestream 1940 m, This is a moderate sized stream, 23.5 arises on the slopes leading to fue vo1cano and km from Carrizal on the road to Poas Vo1cano. passes through sorne pasture land. Stream No. The stream is about 30 cm deep and 3 m 45a (La Georgina, San José), altitude 3150 m, wide, with a bed of mostly stones and large is a small, non permanent stream, located boulders. The stream is fully shaded by large between Km 96 and Km 97 at one side of trees. The waterflow is fast with extreme Interamerican high way to San Isidro de El turbulence as the water passes over and General, near the locality known as "La Geor­ between the large boulders. The water is most1y gina". The number 45a assigned to this stream c1ear with no evidence of pollution. is not inc1uded in the original stream chart of Temperature ranges from 12 to 17 C. The Vargas and Travis (1973). The stream runs stream arises from the nearby slopes and passes down a steep slope, and its bed consists of through pasture lands. Stream No. 42 (San rocks, boulders and mudo The water flow is Juan de Chicuá, Oreamuno, Cartago) altitude from slow to moderate, is c1ear and apparent1y 2.790 m is a small stream 22.5 km from the unpolluted, with pH values from 7.1 to 7.8 Church "Los Angeles" in Cartago, on the road and temperature ranges from 10 to 14 C. to the Irazú Vo1cano. The stream is 5 cm deep Stream No. 73 (Río Reventado, Prusia, Orea­ and about 0.25 m wide, with a bed of stones, muno, Cartago), altitude 2340 m, is a moderate boulders and vo1canic ash. The waterflow is size stream located 0.5 Km NW from the from moderate to fast with riffles where the "Sanatorio Durán". The stream is 0.2 to 0.5 water flows over the large boulders. The water m deep and with a very widely spread bed is mostly c1ear with a small amount of turbidity of 8 m, but with little water volume. The bed caused by the fine vo1canic ash; there is no consists main1y of mud, silt and rocks, covered apparent pollution. In sorne places, there is by a ferrugineoussubstance. There is no trailing 468 REVISTA DE BIOLOGIA TROPICAL

vegetation. It is partially shaded by trees and the respiratory organ of the pupa having shmbs. The water is yellowish, very turbid branches of a digitiform type, and the other, and polluted by volcanic substance and ashes G. bierigí to the subgroup with filiform type and flows over large rocks. Temperature ranges of branches. from 15 to 19 C. This stream arises on the Among the five known species with a slopes of Irazú V olcano and flows through respiratory organ of a digitiform type, the cultivated areas and pasture lands. on1y one with single, undivided branches is G. wittmeri, which according to Wygodzins­ DISCUSSION ky (1951), has only four branches instead of the five present in G. willei. Gigantodax Edwards (1931) split Gigantodax in two bierigí on the other hand, belongs to the groups according to the size and shape of the subgroup of nine known species with a filiform second hind tarsal segment, size of the adults, type respiratory organ. and shape of the cocoon. Wygodzinsky (1962) Eight of these species have 17 or 18 terminal emphasized that the taxonomy of the genus filaments and one has 90-120 terminal fila­ ments. In contrast, our species shows five Gigantodax has its basis not in the morphology of the adult, but in the stmctures of the larval main basal tmnks and seven terminal filaments, and pupal stages which have the best specific all corrugated, and most of them with characters. We can artificially divide the pupal caducous filaments. forms into the following five subgroups, according to the general shape and branching ACKNOWLEDGEMENTS of the respiratory organ (Dalmat 1955, D' An­ dretta & D' Andretta 1947, Coscarón & Wy­ We thank R. Echeverry, G. Zúñiga, R. Ga­ godzkinsky 1962, Edwards 1931, Ramírez-Pé­ llardo, C. R. Méndez, J. F. Herrera, A. Solano, rez 1980, Vargas & Díaz-Nájera 1951, F. Fallas, former field and laboratory assistants Wigodzinsky 1951, 1958). Subgroup I who collected part of the material used in this (branches of a filiform type): G. antarcticum, study; Wi1liam González for his invaluable G. bonorinorum, G. chilense, G. fulvescens, help in the laboratory work. The International G. femineum, G. igniculum, G. kuscheli, G. Center for Medical Research and Training ortizi, G. viannamartinsi. Subgroup 11 (branches (ICMRT) funded the investigation supported of a digitiform type): G. aquamarense, G. initially, in part, by the United States Army bettyae, G. convid, G. wittmeri, G. wrighti. Medical Research and Development Command, Subgroup III (branches of a tubuliform type): Contract-DADA-68-C-8023. The findings in G. cervicorne, G. horcotiani, G. wygodzinskyi this report are not to be construed as an official and G. lazoi. Subgroup N (branches of a mixed Department of the Army position unless so digitiform-tubuliform type): G. corniculatum. designated by official documents. Subgroup V (branches arising from a globular The Vicerrectoría de Investigación of the or subglobular base): G. abalosi, G. bolivianum, Universidad de Costa Rica, provided additional G. impossibile. Unfortunately the pupae of financial support, and logistics for the eight species remain undescribed: G. arauca­ continuity of this project. nium, G. brophy, G. margínale, G. nigrescens, The International Committee for Migration G. pennipunctum, G. rufescens, G. rufinotum (CIM) made it possible for J. Ramírez-Pérez and G. shannoni. According to the available to travel to Costa Rica. descriptions, G. bonorinorum, G. chilense, To B. V. Peterson, Systematic Entomology G. fulvescens, G. kuscheli, G. ortizi and G. Laboratory, BBII, ARS, USDA, Washington, viannamartinsi show 18 distal branches with D. C. for his many suggestions and revision a varied branching mode. Gigantodax antarcti­ of the manuscript. cum and G. femineum show two groups of branches (8-10) oppositely directed, and RESUMEN G. igniculum with 90 to 120 distal filaments. It is obvious that sorne of the species described Se describen la hembra, macho, pupa y la by Edwards (1931) need to be revised. Of the larva de Gigantodax bierigí y Gigantodax two Costarican species of Gigantodax described willei n. spp. (Diptera: Simullidae), Tales espe­ here, G. willei belong to the subgroup with cies se diferencian de los otros miembros del VARGAS & RAMIREZ: Gigantodax bierigi & G. willei, two new species 469

género Gigantodax, tomando como base, liidae) fron the Andean Area of Ecuador. J. Med. entre otros, la forma general y número de las Entomol. 25: 541-544. ramas del órgano respiratorio de la pupa. Vargas, L. & A. Díaz-Nájera. 1951. Notas sobre Ambas especies fueron colectadas de quebra­ sistemática y morfología de simúlidos. Rev. Soco das sitas entre los 1940 y 3150 m sobre el nivel Mex. Hist. Nat. 12: 123-208. del mar. Se incluyen algunas observaciones sobre la biología de las dos especies. Vargas, M. & B. V. Travis. 1973. BionomÍa de los si­ múlidos (Diptera: Simulidae) en Costa Rica. IV Localización y descripción de los lugares de reco­ REFERENCES lección. Rev. Biol. Tr

Coscarón, S. & P. Wydod.zinsky, 1962, .Simuliidae Vu1cano, M. A. 196 7. Fami1y Simuliidae, p. 1-44 (Diptera: Insecta) de Tierra del Fuego, Patagonia In A Catalogue of the Diptera of the Americas e Islas Juan Fernández. Acta. lool. Lilloana 18: south of the United States. Dept. lool. Secr. 281-330. Agr. Sao Paulo, N16.

Dalmat, H. 1955. The black (Diptera, Simulii­ Wygodzinsky, P. 1949. Contribuciones al conoci­ dae) of Guatemala and their role as vectors of miento de los Símulüdae Argentinos. 11 Giganto­ onchocerciasis. Smithsonian Misc. Coll. 125-425. dax horcotiani sp. n. de la Provincia de Tucumán (Diptera). Ann. Inst. Med. Reg. 2: 325- 333. D'Andretta, M_ A. V. & C. D'Andretta. 1947. Redes­ criltao de Gigantodax wrighti (Vargas, MartÍnez & Wygodzinsky, P. 1951. Sobre Gigantodax horcotiani DÍaz, 1944) (Diptera: Simuliidae). Papeis Avulsos Wygod.zinsky 1949 y Gigantodax wittmeri sp. n. de Dept. lool. Secr. Agríe. Sao Paulo 8: 23-37. (Díptera: Simuliidae). Ann. Inst. Med. Reg. 3: 199-206 . Edwards, F. W. 1931. Diptera ofPatagonia and South . Part 11. British Museum Nat. Hist. 2: 121- Wygodzinsky, P. 1958. Notas y descripciones de Si­ 154. muliidae Patagónicos y Andinos (Diptera). Acta lool. Lilloana 16 : 121-148. Moncada, L. l., P. Muñoz de Hoyos & M. L. Bueno. 1981. Simuliidae (Insecta: Díptera) de Colombia, Wygodzinsky, P. 1973. Díagnosis of New Species of 111 Descripción de una nueva especie de Giganto­ Gigantodax Enderlein (Símuliidae, Diptera) from dax Enderlein, 1925. Caldasia 13: 301-311. the Northern . J. New York. Ent. Soco 81: 243-246. Ramírez-Pérez, 1. 1980. Descripción de dos nuevas especies del género Gigantodax Enderlein (Dip­ Wygodzinsky, P. & S. Coscarón. 1973. Review of the tera, Simuliidae) del estado Mérida (Venezuela). Mesoamerican and South American black flies of Bol. Direc. Malariol. San. Amb. 20: 52-58. the tribe (, Símuliidae). Bull. Amer. Mus. Nat. Híst. 151: 131-199. Takaoka, H., H. Hirai & 1. Tada. 1988. Description of a New Species of Gigantodax (Díptera Símu-