Homoneura limnea (Becker 1895)

Semelbauer, Marek & Kozánek, Milan, 2014, The immatures of lauxaniid flies (Diptera: Lauxaniidae) and their taxonomical implications, Zootaxa 3780 (3), pp. 401-454 : 410-412

Homoneura limnea (Becker 1895)

Living larvae moderately dorsoventrally flattened, the distal parts of Malpighian tubules expanded.

Egg ( Figs 6–8 ). Length 0.65–0.78 mm. Ridges prominent, not fusing, edge of the ridges can bear irregular denticles. The posterior pole with prominent tubercle. Chorion tuberculous, with fine rectangular net laid over, the transversal septa very dense.

First instar ( Figs 45–48 ). Length 0.95–1.15 mm. The ventral organ with two simple digitiform projections. The first thoracic segment with broad band of comb spines anterodorsally, second one completely smooth, third one with narrow band of comb spines both dorsally and ventrally. Dorsal creeping welts of the first abdominal segments with comb spines, towards the posterior end successively changing into simple spines. Processes of the anal division slightly indicated.

Cephaloskeleton ( Fig. 164 ). Length 0.25–0.26 mm. Mouth hooks with 4–5 teeth, stalked part hyaline and widely separated. Labrum with three distinct corners from the dorsal view.

Second instar ( Fig. 49 ). Length 1.25–3.26 mm. The characters of external morphology similar to previous species.

Cephaloskeleton ( Fig. 179 ). Length 0.33–0.38 mm. The mouth hooks converging, with 2–3 apical teeth. Ventral bridge narrow. Epistomal sclerite shorter than broad, with posterior hyaline plate. Ligulate sclerites as vertical converging plates. Subhypostomal sclerite as arched bars with anterior swelling. Dorsal bridge longer than broad. Ventral cornua with posterior third hyaline.

Third instar ( Figs 50–58 ). Length 3.05–6.12 mm. The facial mask very similar to previous species, as well as the pattern of spinulation on body segments. The anterior spiracles fan-shaped with 7 papillae.

Cephaloskeleton ( Fig. 194 ). Length 0.65–0.71 mm. The mouth hooks converging. The ventral bridge of intermediate sclerite narrow. The epistomal sclerite shorter than broad with posterior hyaline plate. Ligulate sclerites as converging vertical plates. Subhypostomal sclerite parallel with almost opposite tips. Dorsal bridge longer than broad, anteriorly rounded. The posterior third of ventral cornua hyaline, but the dorsal edge slightly sclerotised.

Figures

FIGURES 1 – 8. Eggs of Cnemacantha muscaria, Homoneura biumbrata and H. limnea. 1. C. muscaria, dorsal view. 2. Same, detail of egg chorion. 3. H. biumbrata, dorsal view. 4. Same, lateral view of posterior tubercle. 5. Same, detail of the egg chorion. 6. H. limnea, ventral view. 7. Same, detail of the posterior tubercle. 8. Same, detail of the egg chorion.

FIGURES 45 – 48. Homoneura limnea, first instar. 45. Cephalic segment, ventral view. 46. Detail of ventral organ, anterior view. 47. Cephalic and first two thoracic segments, lateral view. 48. Anal division and last abdominal segment, lateral view. A, antenna; A 3 – A 5, third to fifth abdominal segments; LL, labial lobe; MH, mouth hook, PC, peristomal cirri; PS, posterior spiracles; SC, scraping cirri, SC 1, first row of scraping cirri; T 1 – T 2, first to second thoracic segments; VO, ventral organ.

FIGURES 162 – 167. Cephaloskeletons of first larval instar, dorsal (top), lateral (middle) and ventral (bottom) view. 162. Cnemacantha muscaria. 163. Homoneura biumbrata. 164. H. limnea. 165. Minettia austriaca. 166. M. fasciata. 167. M. flaviventris. c, cibarium; db, dorsal bridge; dc, dorsal cornua; dmh, distal part of mouth hook; es, epistomal sclerite; is, intermediate sclerite; lb, labrum; ls, ligulate sclerite; smh, stalked part of mouth hook; pb, parastomal bar; ss, subhypostomal sclerite; vb, ventral bridge; vc, ventral cornua; vp, vertical plate.

FIGURES 49 – 54. Homoneura limnea, second (49) and third (50 – 54) instars. 49. Cephalic segment, frontal view. 50. Cephalic segment, ventral view. 51. Detail of the ventral organ. 52. Cephalic and thoracic segments, lateral view. 53. Anterior spiracle, lateral view. 54. Keilin's organ on the first thoracic segment, ventral view. A, antenna; AS, anterior spiracles; CS, cephalic segment; LL, labial lobe; MH, mouth hooks; MP, maxillary palpus; PC, peristomal cirri; SC, scraping cirri; T 2, second thoracic segment; VO, ventral organ.

FIGURES 177 – 182. Cephaloskeletons of second larval instar, dorsal (top), lateral (middle) and ventral (bottom) view. 177. Cnemacantha muscaria. 178. Homoneura biumbrata. 179. H. limnea. 180. Minettia austriaca. 181. M. fasciata. 182. M. flaviventris. a, apodeme of ventral cornu c, cibarium; db, dorsal bridge; dc, dorsal cornua; ds, dental sclerite; es, epistomal sclerite; is, intermediate sclerite; lb, labrum; ls, ligulate sclerite; mh, mouth hook; pb, parastomal bar; r, rami; ss, subhypostomal sclerite; vb, ventral bridge; vc, ventral cornua; vp, vertical plate.

FIGURES 192 – 197. Cephaloskeletons of third larval instar, dorsal (top), lateral (middle) and ventral (bottom) view. 192. Cnemacantha muscaria. 193. Homoneura biumbrata. 194. H. limnea. 195. Minettia austriaca. 196. M. fasciata. 197. M. flaviventris. a, apodeme of ventral cornu; c, cibarium; db, dorsal bridge; dc, dorsal cornua; es, epistomal sclerite; is, intermediate sclerite; lb, labrum; ls, ligulate sclerite; mh, mouth hook; pb, parastomal bar; r, rami; ss, subhypostomal sclerite; vb, ventral bridge; vc, ventral cornua; vp, vertical plate.