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Dixella suzukii Chaverri and Borkent n. sp. (Figures 1J, 3D, 5D, 6J, 9C, 14B, 17, 19B) Diagnosis. Male: only species of Dixidae in Central America with a short, conical gonostylus (Fig. 14B). Female: only species of Dixidae in Central America with a short lobe protruding from the lateral margin of abdominal segment 10 (Fig. 17). Description. Male. Head (Fig. 1J): brown, densely spiculate. Clypeus brown, as wide as long. Antennal scape, pedicel brown, flagellomeres yellowish. Thorax (Fig. 3D, 5D): scutum with wide dark brown medial vitta extending from anterior margin to middle of scutum, continuing as lighter, narrower brown band to supraalar area; lateral dark brown vitta broadly joined to medial vitta anteriorly near prescutal suture, extending to supraalar area, lateral margin notched above spiracular area. Scutellum, mediotergite dark brown. Pleura dark brown, somewhat patterned, except pronotum yellowish, katepisternum with yellow area on posterior margin. Wing (Fig. 6J; Table 1): with slight darkening over r-m; R2+3 originating at or distal to r-m; stem of R2+3 0.47 length of R3. Halter: pale, 0.30 length of fore femur. Legs: coxae, trochanters brown; femora yellowish with brown apices; tibiae, tarsi uniformly pale brown; claws as figured (Fig. 9C). Genitalia (Fig. 14B): tergite 9 with anterior margin somewhat concave, posterior margin straight, with numerous scattered setae. Sternite 9 with posterior margin with moderately broad excavation, with 5 elongate lateral setae. Gonocoxite as long as wide; basal lobe absent; apical lobe slightly longer than gonostylus, triangular apex with sharp ventral lobule and elongate dorsal lobule, stem with three elongate seta, one short subapical seta. Gonostylus densely spiculate, with elongate setae, broad basally, tapering gradually to apex. Parameres directed anteriorly, tips rounded, convergent. Aedeagus brown, elongate, narrow, directed posteriorly. Tergite 10 with narrow lateral band, posterolateral expansion, posteromedially with pair of protrusions. Female. As for male, with following differences: Wing (Table 2). Genitalia (Fig. 17): sternite 8 with posterior margin concave medially, medial bulge with dense patch of setae, slightly wider posteriorly, with more setae than previous sternites; tergite 9 dark brown, posterolateral margin rounded, anteroventral margin notched; sternite 9 narrow, with sublateral ventral bulge; segment 10 as long as cercus, with scattered setae, with small basal protuberance; cercus short, slightly wider at base, with elongate setae. Immatures: not described. Distribution and bionomics. This species is known from two localities in Costa Rica and two localities in Panama (Fig. 19B) at 660–1585 m. In Costa Rica the habitat in which specimens were collected corresponds to Premontane Very Wet Forest. Larvae from the type locality were collected from a seepage pool with muddy substrate in a grazing area during the dry season (April). The male from 3 km E of Cambronero, Costa Rica was reared from a larva collected from a "wide shallow seepage from roadside bank in grazing area; water semipermanent, clear, with slow current; choked with grasses; bottom with mud, much dead grass; full sun" (Heinemann and Belkin, 1977) during the rainy season (August). Adults from Panama were collected in light traps. Taxonomic discussion. We studied males and females reared from identical larvae and pupae from the type locality, indicating that they are conspecific. Heinemann and Belkin (1977) recorded this species as Dixella sp. 1 with the following specimens in the USNM labled as such: CR 352-23 and 352-25. There are additional specimens of five associated larval and pupal exuviae labeled as Dixella sp. 1 which may conspecific with D. suzukii (CR352-20-22, 24, 26) but these were not associated with any adults and therefore are of uncertain identity. Types. Holotype, male adult on microscope slide, labeled " HOLOTYPE Dixella suzukii Chaverri and Borkent ", " Costa Rica, Cartago, Orosí, P.N. Tapantí-Macizo de La Muerte, orilla del puente del río Grande de Orosí, 1200 m, 27-IV-2001, B.H. Hernández, En charco, LN 259000 558850, BHB 470.30, larva and pupal exuviae associated" (INBC). Allotype, female adult on microscope slide labeled as holotype but with code BHB 470.36, (INBC). Paratypes: 5♂, 8 ♀, on microscope slides labeled as above but with codes BHB 470.13, BHB 470.14, BHB 470.38, BHB 470.22 (larva and pupal exuviae associated), BHB 470.35, BHB 470.05 (larva and pupal exuviae associated), BHB 470.12, BHB 470.21, BHB 470.37, BHB 470.24, BHB 470.27 (pupal exuviae associated), BHB 470.34, BHB 470 (3♂, 4 ♀, INBC; 1♂, 2 ♀, CNCI; 1♂, 2 ♀, USNM); 1♂, 1 ♀ on microscope slide, each with larval and pupal exuviae on separate microscope slides: Costa Rica, Alajuela, 12.7 km W of San Ramon on Natl. Rt. 1, about 3km E of Cambronero, 770 m, 13-VIII-1971, S.J. Heinemann (USNM); 1♂ on microscope slide: Panama, Chiriqui, Chiriqui ViejoR. El Volcan 22-VII-1966, A. Broce, light trap (USNM); 1 ♀ on microscope slide: Panama, David, Chiriqui, 24-VII-1964, A. Broce, light trap (USNM). Derivation of specific epithet. We name this species suzukii to honour David T. Suzuki, a Canadian environmentalist who has devoted his life teaching the public about of the state of our earth and the importance of taking better care of our world., Published as part of Chaverri, Luis Guillermo & Borkent, Art, 2007, The Meniscus midges of Costa Rica (Diptera: Dixidae), pp. 1-34 in Zootaxa 1575 (1) on pages 28-30, DOI: 10.11646/zootaxa.1575.1.1, http://zenodo.org/record/5096833, {"references":["Heinemann, S. J. & Belkin, J. N. (1977) Collection records of the project \" Mosquitoes of Middle America \". 7. Costa Rica. Mosquito Systematics, 9, 237 - 287."]}

Dixella jironi Chaverri and Borkent n. sp. (Figures 1F, 6F, 8B, 12B, 18B) Diagnosis. Male: only species of Dixidae in Central America with a wide pale medial band on the pleura extending from the anterior margin of the katepisternum to the posterior margin of the anepimeron and with the gonostylus apically tapered (Fig. 12B). Female: unknown. Description. Male. Head (Fig. 1F): brown, densely spiculate, with spicules more elongate than those in D. shannoni, D. hansoni, D. fernandezae. Clypeus yellowish, as wide as long. Antennal scape, pedicel, flagellomeres yellowish. Thorax: similar to D. shannoni (Fig. 2C, 4C). Scutum yellowish, with narrow lateral light brown band extending from anterior margin, widening near prescutal suture, continuing laterally to supraalar area, anterior to middle of scutum lateral band continues medially as faint yellow line, with row of setae to prescutellar area; acrostical, anterior dorsocentral, supraalar setae short, scattered. Scutellum, mediotergite brown. Pleura with 2 setae on posteroventral margin of posterior anepisternum. Wing (Fig. 6F; Table 1): with or without slight darkening over r-m; R2+3 originating either at or slightly distal to r-m; stem of R2+3 0.40 length of R3. Halter: pale, 0.40 length of fore femur. Legs: yellowish; claws as figured (Fig. 8B). Genitalia (Fig. 12B): tergite 9 with anterior, posterior margins curved, with setae more dense along posterior margin. Sternite 9 with posterior margin with moderately narrow excavation, with 3–4 posterolateral setae. Gonocoxite longer than wide; basal lobe quadrate; apical lobe cylindrical, tusk-like, slightly curved dorsally, tip rounded, 0.6 length of gonostylus, with elongate basal seta, midlength seta as long as half lobe length, two short subapical setae. Gonostylus slightly wider at base and apex, apex rounded, with short subapical seta. Parameres dark brown, narrow, sinuous, pointed, apices directed posteriorly. Aedeagus triangular. Tergite10 light brown, posterior margin slightly bilobed, with four short subapical setae. Female and immatures. Unknown. Distribution and bionomics. Dixella jironi is known only from the type locality in Costa Rica at 1700 m (Fig. 18B). Adults were swept from low vegetation near a small stream at the beginning of rainy season (May) in a habitat corresponding to Premontane Moist Forest. Taxonomic discussion. The male adult of this species shares the medial pale band on the thoracic pleura of D. shannoni and D. hansoni. The apical lobe of the gonocoxite of the male genitalia is similar in the three species but in D. jironi it is longer, relative to the gonostylus. Further differences are present in the shape of the parameres, gonostyli and the tenth sternites of these three species (see key, Figs. 11A, B, 12B). Types. Holotype, male adult on microscope slide, labeled " HOLOTYPE Dixella jironi Chaverri and Borkent ", " Costa Rica, San José, Escazú, Alto Tapezco, 1700 m, 31-V-1999, A. Borkent, LN 209100 518900" (CNCI). Paratypes: 3♂ on microscope slide (1♂, INBC; 2♂, CNCI). Derivation of specific epithet. This species is named for Luis Fernando Jiron, a former entomology professor at the Universidad de Costa Rica who has published extensively on fruit flies (Diptera: Tephritidae) and who was a student advisor to the first author., Published as part of Chaverri, Luis Guillermo & Borkent, Art, 2007, The Meniscus midges of Costa Rica (Diptera: Dixidae), pp. 1-34 in Zootaxa 1575 (1) on pages 17-18, DOI: 10.11646/zootaxa.1575.1.1, http://zenodo.org/record/5096833

Dixella hansoni Chaverri and Borkent n. sp. (Figures 1D, 2D, 4D, 6D, 7D, 11B, 18B) Diagnosis. Male: only species of Dixidae in Central America with a wide pale medial band on the pleura extending from the anterior margin of the katepisternum to the posterior margin of the anepimeron (Fig. 4D), with R2+3 originating distal to r-m (fig. 6D), and with the aedeagus bilobed anteriorly (Fig. 11B). Female: unknown. Description. Male. Head (Fig. 1D): brown, densely spiculate. Clypeus brown, as wide as long. Antennal scape, pedicel brown, flagellomeres yellowish. Thorax (Fig. 2D, 4D): scutum yellowish, broad anterolateral brown line narrowing posterolaterally; lateral band continues medially as faint yellow line anterior to middle of scutum to prescutellar area, with single row of elongate setae; acrostical, anterior dorsocentral, supraalar setae short, scattered. Scutellum brown, mediotergite yellowish. Pleura with pronotum yellowish, propleuron, katepisternum, posterior anepisternum, anepimeron, metanepisternum brown; medial yellow strip extending from katepisternum to anterior half of anepimeron; 2 setae on posteroventral margin of posterior anepisternum. Wing (Fig. 6D; Table 1): with or without slight darkening over r-m; R2+3 originating distal to r-m; stem of R2+3 0.55 length of R3. Halter: pale, 0.45 length of fore femur. Legs yellowish; claws as figured (Fig. 7D). Genitalia (Fig. 11B): tergite 9 with anterior, posterior margins nearly straight, with scattered setae, more sparse medially. Sternite 9 with posterior margin with broad excavation, with one submedial, two lateral setae. Gonocoxite as long as wide; basal lobe rounded, medial margin somewhat rounded; apical lobe cylindrical, tusk-like, slightly curved dorsally, tip acute, 0.50 length of gonostylus, with elongate basal seta, elongate midlength seta, two short subapical setae. Gonostylus slightly swollen at base, apex not swollen, subapical spine not present. Parameres dark brown, narrow, each curved in S shape, apices convergent. Aedeagus as figured. Tergite 10 light brown, anterolateral margin rounded, posterior margin somewhat bilobed, with 1–2 short subapical setae, subbasal lateral brown membrane. Female and immatures. Unknown. Distribution and bionomics. Dixella hansoni is known from a single male in Costa Rica (Fig. 18B), collected at 10 m elevation during the dry season (January). The specimen was swept from the margin of either Quebrada Bonita or a small tributary of this stream. The habitat corresponds to Tropical Moist Forest in the lowlands. Taxonomic discussion. This species is similar to D. shannoni but the medial strip of paler cuticle on the pleura extends posteriorly only to about the anterior half of the anepimeron, the tarsal claws differ in number of teeth, the tip of the apical lobe of the male genitalia is rounded in D. shannoni and acute in D. hansoni, the gonostylus in D. hansoni lacks apical setae, and tergite 10 differs in shape and number of setae in both species. A single female collected from the type locality but on 24-I-1994 (INBC) may represent the female of D. hansoni. However, we were unable to discern any difference between this female and those of D. shannoni and, with the information available, it may belong to either species. Types. Holotype, male adult on microscope slide, labeled " HOLOTYPE Dixella hansoni Chaverri and Borkent ", " Costa Rica, 2 Km NE Tárcoles, Carara NP, 1-I-1994, A. Borkent, CD 1726" (CNCI). Derivation of specific epithet. This species is named for Paul E. Hanson in recognition of his important and continuing research on the Hymenoptera and other insects of Costa Rica and for his invaluable teaching of entomology to the first author., Published as part of Chaverri, Luis Guillermo & Borkent, Art, 2007, The Meniscus midges of Costa Rica (Diptera: Dixidae), pp. 1-34 in Zootaxa 1575 (1) on pages 13-15, DOI: 10.11646/zootaxa.1575.1.1, http://zenodo.org/record/5096833

Dixella lobata Chaverri and Borkent n. sp. (Figures 1I, 3C, 5C, 6I, 9B, 14A, 16B, 19A) Diagnosis. Male: only species of Dixidae in Central America with the apical lobe of the gonocoxite slender and extending nearly to the apex of the gonostylus (Fig. 14A). Female: only species of Dixidae in Central America with a distinct pit on the lateral margin of abdominal segment 10 (Fig. 16B). Description. Male. Head (Fig. 1I): brown, densely spiculate. Clypeus light brown, as wide as long. Antennal scape, pedicel brown, flagellomeres yellowish. Thorax (Fig. 3C, 5C): scutum with wide dark brown medial vitta extending from anterior margin to prescutellar area of scutum, narrowly continuing laterally to supraalar area; lateral dark brown vitta broadly joined to medial vitta anteriorly, extending to supraalar area, lateral margin notched above spiracular area. Scutellum, mediotergite dark brown. Pleura dark brown, somewhat patterned, except as follows: pronotum yellowish, yellowish below, posterior margin of katepisternum with yellow area. Wing (Fig. 6I; Table 1): with slight darkening over r-m; R2+3 originating at r-m; stem of R2+3 elongate, 0.65 length of R3. Halter: pale, 0.30 length of fore femur. Legs: coxae, trochanters brown; femora yellowish with brown apices; tibiae, tarsi uniformly pale brown; claws as figured (Fig. 9B). Genitalia (Fig. 14A): tergite 9 with anterior margin straight, posterior margin concave, with numerous scattered setae. Sternite 9 with posterior margin with broad excavation, with 6–8 elongate lateral setae. Gonocoxite wider than long; basal lobe absent; apical lobe longer than gonostylus, swollen at midlength, three elongate setae beyond midlength, two small subapical setae. Gonostylus densely spiculate, with elongate setae, apex tapering. Parameres directed anteromedially, tips heart-like. Aedeagus as figured. Tergite 10 tapering posteriorly, with posterolateral margin well-developed, protruding, medially with broad distal membrane with pale, difficult to discern, margin. Female. As for male, with following differences: Wing (Table 2). Genitalia (Fig. 16B): sternite 8 with posterior margin straight, with dense patch of medial setae; tergite 9 dark brown, lateral margin with posteriorly directed projection; tergite 9 with elongate, setose, posterolateral protuberance; sternite 9 narrow, anterior margin irregular, basal projection oriented anteromedially; segment 10 with apex truncate, 3–4 elongate subapical setae, 5 marginal setae shorter; cercus wide at base. Immatures. not described. Distribution and bionomics. This species is known from two localities in Costa Rica at elevations of 1540–2405 m (Fig. 19A) and is present during the wet season (July) and in virtually continuously wet habitats (March). Pupae and possibly larvae were found in ground pools, margins of a slowly moving stream (without fish) and in a seepage pool with a muddy substrate in a pasture. The specimens collected from 11 km N of San Isidro, Costa Rica, were collected as larvae from a ground pool. The habitats correspond to Premontane Moist Forest and Premontane Very Wet Forest transitional to Pluvial. Taxonomic discussion. Adult C. lobata have the same pigmentation and wing characters as those of D. suzukii, but males of the two species are easily distinguished by their genitalia (see key; Figs. 14A, B). The male genitalia of this species exhibited significant variation in the shape of the gonostylus (tapering to rounded apically), the shape of the apical lobe of the gonocoxite (some more slender and sinuous), and the shape of the basal lobe of the gonocoxite. Further interpretation of such variation must await additional specimens. Heinemann and Belkin (1977) recorded this species as Dixella sp. 2, with the following specimens in the USNM labeled as such: CR 303-10, 101 and 303-100. The USNM has one male (lacking its genitalia and probably slide mounted earlier but apparently missing), with associated larval and pupal exuviae, one additional associated larval and pupal exuviae and one single larval exuviae all of which may be conspecific with D. lobata (CR303-11-13). Two specimens of D. lobata from 11 km N of San Isidro were identified as Dixella species 1 (?) by Heinemann and Belkin (1977). Types. Holotype, male adult on microscope slide, labeled " HOLOTYPE Dixella lobata Chaverri and Borkent ", " Costa Rica, Limón, Talamanca, Bratsi, Parque Internacional La Amistad, Valle del Silencio, 2405 m, 21-III-2003, G. Chaverri, En charco, LS 341222 577399, LGCh 582.01" (INBC). Allotype, female adult on microscope slide labeled as holotype with code LGCh 582.03 (INBC). Paratypes: 2♂, 1 ♀, on microscope slide labeled as holotype but with codes LGCh 582.02, 582.05 respectively (1♂, INBC; 1♂, 1 ♀, CNCI); 3♂, on microscope slides, one with associated larval and pupal exuviae, two with pupal exuviae, exuviae of all three on separate slides: Costa Rica, San Jose, San Isidro de Coronado, 5 km E of Rt. 216 junction on Natl. Rt. 6 and 0.2 km N on road to bridge over Rio Durazno, about 0.3 km W of bridge, 1540 m, 30-VII-1971, S.J. Heinemann (USNM); 2♂ on microscope slide: Costa Rica, San José, La Ese, 11 km N of San Isidro on Natl. Rt. 2, 1300m, 20-XI-1962, R. Casebeer, C. Hogue & W. Powder, with codes 32 (without genitalia) and 32- 202 (USNM). Derivation of specific epithet. The name lobata (lobe) refers to the short, setose, protuberance arising from the posterolateral margin of segment 9 of the female adult, a unique feature at least in Central America., Published as part of Chaverri, Luis Guillermo & Borkent, Art, 2007, The Meniscus midges of Costa Rica (Diptera: Dixidae), pp. 1-34 in Zootaxa 1575 (1) on pages 24-28, DOI: 10.11646/zootaxa.1575.1.1, http://zenodo.org/record/5096833, {"references":["Heinemann, S. J. & Belkin, J. N. (1977) Collection records of the project \" Mosquitoes of Middle America \". 7. Costa Rica. Mosquito Systematics, 9, 237 - 287."]}

Dixella fernandezae Chaverri and Borkent n. sp. (Figures 1E, 6E, 8A, 12A, 18B) Diagnosis. Male: only species of Dixidae in Central America with a short clypeus (Fig. 1E), uniformly dark pleura, R2+3 originating distal to r-m, and with the subapical gonocoxal lobe short and not extending beyond the apex of the gonocoxite (Fig. 12A). Female: unknown. Description. Male. Head (Fig. 1E): brown, densely spiculate. Clypeus yellowish, 1.2 wider than long. Antennal scape, pedicel brown, flagellomeres lost. Thorax: scutum not visible. Scutellum brown, mediotergite yellowish. Pleura with pronotum, propleuron brown; posteroapical region of katepisternum, basal anepimeron yellowish; 2 setae on posteroventral margin of posterior anepisternum. Wing (Fig. 6E; Table 1): with or without slight darkening over r-m; R2+3 originating distal to r-m; stem of R2+3 0.50 length of R3. Halter: pale, 0.40 length of fore femur. Legs: yellowish; claws as figured, hind claws not visible (Fig. 8A). Genitalia (Fig. 12A): tergite 9 with anterior, posterior margins nearly straight, with scattered setae. Sternite 9 with posterior margin with broad excavation, with three lateral setae. Gonocoxite wider than long; basal lobe not well defined; apical lobe cylindrical, tusk-like, slightly curved dorsally, tip acute, 0.50 length of gonostylus, with elongate basal seta, elongate midlength seta, two short subapical setae. Gonostylus slightly wider at base, tapering gradually to apex, apex acute, four elongate subapical setae. Parameres dark brown, narrow, directed dorsally, apices divergent. Aedeagus triangular. Tergite 10 light brown, with anterolateral extension posterior margin slightly bilobed, with three short subapical setae. Female and immatures. Unknown. Distribution and bionomics. This species is known only from the type locality in Costa Rica at 1540 m (Fig. 18B) and has been collected during the dry season (June). The holotype was swept from vegetation in an area of several small streams. The habitat corresponds to Tropical Lower Montane Rainforest. Taxonomic discussion. The apical lobe of the gonocoxite is similar to that of D. hansoni but the shapes of the parameres and aedeagus are distinctive (see key) (Figs. 11B, 12A). Types. Holotype, male adult on microscope slide, labeled " HOLOTYPE Dixella fernandezae Chaverri and Borkent ", " Costa Rica, Puntarenas, Monteverde, 2 Km E. de Santa Elena, Estación Biológica Monteverde, 1540 m, 12-VI-2000, A. Borkent, CD 5085, LN 255800 447900" (CNCI). Derivation of specific epithet. This species is named in recognition of the contribution of Xinia Fernández, a former technician working at INBio, who reared numerous nematocerous Diptera (and especially Culicidae) and prepared a large collection of microscope slides., Published as part of Chaverri, Luis Guillermo & Borkent, Art, 2007, The Meniscus midges of Costa Rica (Diptera: Dixidae), pp. 1-34 in Zootaxa 1575 (1) on pages 15-17, DOI: 10.11646/zootaxa.1575.1.1, http://zenodo.org/record/5096833