Lauxania minor

Semelbauer, Marek & Kozánek, Milan, 2012, Morphology of preimaginal stages of Lauxania and Calliopum (Diptera: Lauxaniidae), Zootaxa 3346, pp. 1-28 : 23

Lauxania minor

Egg ( Figs 2, 4 ). 0.59–0.65 mm. Dorsal side with straight, occasionally fusing ridges and perforated chorion. Ventral side with undulated and often fusing ridges, chorion covered by smooth layer.

First larval instar. Length 0.67–1.51 mm. Six teeth on distal part of mouth hook ( Fig 5 ). Length of cephaloskeleton: 0.17–0.24 mm ( Fig. 109 ).

Second larval instar. Length 1.48–2.98 mm. No unique character was found. Length of cephaloskeleton: 0.28 –0.39 mm ( Fig. 110 ).

Third larval instar. Length 2.91–4.44 mm. Posterior border of first thoracic segment with broad smooth area ( Fig. 16 ), posterior border of second and third thoracic segment with sparse comb spines ( Fig. 19 ). Anterior spiracles with 9 papillae, the upper-most papilla curved back ( Fig 17 ).

Integument of abdominal segments with large smooth area behind anterior creeping welt on dorsal and ventral sides. Two tubercules located inside the dorsal smooth area. Two smaller tubercules more laterally, outside the dorsal smooth area ( Fig 20 ).

Length of cepahlopharyngeal skeleton: 0.56–0.61 mm. Cepahlopharyngeal skeleton ( Fig. 111 ) markedly compressed dorsoventrally (approximately 0, 11 mm high). Dorsoventral axis of mouth hooks almost parallel. Intermediate sclerite slightly bent from lateral view. Ventral cornua not pressed inward on dorsal margin between vertical plate and apodeme of ventral cornu.

Puparium ( Fig. 115 ). Length 2.94–3.24 mm. From lateral view, the puparium is somewhat dropshaped, with the acute anterior end. Crevices create small medial ovals on dorsal side.

Figures

FIGURES 1 – 4. Eggs of Lauxania cylindricornis and L. minor. 1 – L. cylindricornis, oriented with posterior end to left. 2. L. minor, oriented with posterior end to left. 3. L. cylindricornis, detail of posterior tubercle. 4. L. minor, detail of posterior tubercle.

FIGURES 5 – 8. First instar of L. cylindricornis and L. minor. 5. L. minor, pseudocephalon, ventral view. 6. L. minor, detail of ventral organ. 7. L. cylindricornis, pseudocephalon, ventral view. 8. L. cylindricornis, detail of ventral organ and mouth hook. C, cirri; C 1, first row of cirri; LL, labial lobe; LS, labial sensilla; MH, mouth hook; VO, ventral organ.

FIGURES 107 – 112. Cephaloskeletons of L. cylindricornis (left column) an L. minor (right colum). From the top for each figure: dorsal, lateral and ventral view. 107. L. cylindricornis, first instar. 110. L. minor, first instar. 108. L. cylindricornis second instar. 111. L. minor, second instar. 109. L. cylindricornis, third instar 112. L. minor, third instar. db, dorsal bridge; dc, dorsal cornu; ds, dental sclerite; es, epistomal sclerite; dmh, dentate part of mouth hook; is, intermediate sclerite; lb, labrum; ls, ligulate sclerite; mh, mouth hook; pb, parastomal bar; ph, pharynx; r, rami; smh, stalk part of mouth hook; ss, subhypostomal sclerite; vb, ventral bridge; vc, ventral cornu; vp, vertical plate.

FIGURES 13 – 18. Lauxania minor, third instar, arrowheads indicate the tubercles. 13. Pseudocephalon, ventral view. 14. Maxillary palpus. 15. Ventral organ. 16. Pseudocephalon and first thoracic segment, dorsal view. 17. Anterior spiracle. 18. Keilin’s organ. A, antenna; C, cirri; CS, pseudocephalon; LL, labial lobe; MH, mouth hook; MP, maxillary palpus; NS 1, NS 2, first and second additional sensilla; SB 1 – SB 4, first to fourth sensilla basiconica; SC 1 – SC 4, first to fourth sensilla coeloconica; VOventral organ.

FIGURES 19 – 22. Lauxania minor, third instar, arrows indicate the borders between segments, arrowheads indicate the tubercles. 19. Second and third thoracic segment, dorsal view. 20. Abdominal segments, dorsal view. 21. Abdominal segments, lateral view. 22. Abdominal segments, ventral view. A 6 – A 8, sixth to eighth abdominal segments; ACW, anterior creeping welt; AS, anterior spiracle; PCW, posterior creeping welt; MCW, medial creeping welt; VCW, ventral creeping welt.

FIGURES 113 – 115. Cephaloskeleton of C. splendidum. From the top for each figure: dorsal, lateral and ventral view. 113. First instar. 114. Second instar. 115. Third instar. db, dorsal bridge; dc, dorsal cornu; ds, dental sclerite; es, epistomal sclerite; dmh, dentate part of mouth hook; is, intermediate sclerite; lb, labrum; ls, ligulate sclerite; mh, mouth hook; pb, parastomal bar; ph, pharynx; r, rami; smh, stalk part of mouth hook; ss, subhypostomal sclerite; vb, ventral bridge; vc, ventral cornu; vp, vertical plate.