Dasybasis (D.) pruinivitta (Kröber), Krober

González, Christian R., 2004, The immature stages of Dasybasis (Dasybasis) pruinivitta (Kröber), from Central Chile (Diptera: Tabanidae), Zootaxa 573, pp. 1-7 : 3-4

Dasybasis (D.) pruinivitta (Kröber)

Description. Mature larva: length 20.0–22.0 mm, dark green with whitish areas, particularly in anal segment. Body without trichomes, pseudopodia well developed and con­

colorous and with posteriorly recumbent spines on the apex; body fully striated ( Fig. 1 ).

Cephalic capsule dark brown, 4.1–4.5 mm long, greatest width 0.8–0.9 mm. Clypeus pale brown, slightly upturned. Mandibles dark brown, slender, curved, with serrations ventrally, length 0.45–0.5 mm ( Fig. 2 ). Antenna three segmented; basal segment broad and longest; second slender, 0.32 mm and 0.15 mm, respectively; third segment short, bifid, 0.027 mm long ( Fig. 2 ). Maxillary palpi relatively short, third segment 0.4 times the second segment ( Fig. 2 ). Cephalic brushes present. Prothorax bearing pubescence. Body fully striated. Prothorax with dorsal striations separated by 0.081 mm, laterally 0.087 mm. Meso­ and metathoracic segments with striations separated by 0.092–0.098 mm dorsally and 0.093 mm ventrally. Segments IV–XI with striations separated by 0.074–0.08 mm laterally, 0.095–0.099 mm dorsally and 0.097–0.099 mm ventrally. Pubescence on all body segments but not measured, lightly pigmented. Anterior pubescence forming a ring on pro­, meso­, and metathorax. Anterior pubescence complete on segment IV; incomplete on segments V–X. Posterior abdominal pubescence forming a complete ring on segment X, reduced on segment III­IX. Pseudopodial pubescence complete on segment IV to X but with slight interruptions. Anal segment 1.3–1.4 mm long, height 2.2–2.4 mm ( Fig. 3, 4 ). Anal ridge with fine, abundant pubescence ( Fig. 5 ). Respiratory siphon short 0.25–0.40 mm long, width 0.41–0.43 mm and with four short setae. Tracheal trunks 0.75–0.79 mm long and 0.36–0.39 mm wide. Graber’s organ not visible in the living larva.

Pupa: maximun length 16.0–18.0 mm, light brown, darker near thoracic spiracles ( Fig. 6 ). Frontal tubercles wrinkled and separated, raised 0.12–0.15 mm. Antennal ridge undivided, median and lateral portions not well separated. Antennal sheaths reaching epicranial suture and annulated, 0.62–0.65 mm long, 0.41 mm wide ( Fig. 7 ). Callus tubercle subcircular, wrinkled, elevated, well sclerotized, length 0.14–0.18, each bearing one short seta 0.11–0.15 mm long ( Fig. 8 ). Vertical setae 0.35–0.37 mm long; one pair of lateral orbital setae, 0.22–0.25 mm long; anterior orbital setae 0.25–0.29 mm long, posterior orbital setae 0.19–0.22 mm long. Thoracic spiracles 0.75–0.85 mm long, shaped as in Fig. 9 and situated near epicranial suture; spiracular prominences not exceeding anterodorsal margin of thorax. One pair of basalalar setae present, 0.29–0.31 mm long and one pair of anterior mesonotal setae, 0.22 mm long; one pair of posterior mesonotal setae 0.18 mm long. Three pairs of metanotal setae present sublaterally 0.15–0.19 mm long, close together, one pair situated anterolaterally at the basal angle of the wing sheaths, 0.15–0.17 mm long. First abdominal segment with one pair of tergal setae, 0.12–0.14 mm long and three pairs of pleural setae, 0.16–0.18 mm long, quite close together, situated anteriorly. Abdominal fringe spines biseriate; spines slender and long; spines of posterior series longer than spines of anterior series. Pleural spines similar to tergal and sternal spines on all segments. Tergum of abdominal segments II to VI with about 53–66 well developed spines on the posterior border, biseriate and variable in size, anterior series smaller than posterior series, longest 0.20–0.22 mm long. Abdominal segment VII with 40–49 spines, longer than on other segments, the longest 0.35–0.40 mm. Terminal aster small, 0.50–0.55 mm long, sharply pointed, with lateral tubercles well developed; dorsal tubercles divergent, oriented dorsally 0.28–0.35 mm long, longer than lateral and ventral tubercles; lateral tubercles widely divergent, oriented laterally, 0.17–0.20 mm long; ventral tubercles divergent, oriented posteriorly, 0.19–0.24 mm long ( Fig. 10 ). Anal tubercles protuberant in the male and with ventral preanal comb of spines uninterrupted, with 37–42 spines ( Fig. 11 ). Dorsolateral preanal comb with 2–3 spines; lateral preanal comb with 3 spines.

Figures

FIGURES 1 – 5. Dasybasis (D.) pruinivitta (Kröber), larva. 1, general aspect of mature larva in lateral view (1 – 3, thoracic segments, I – VIII, abdominal segments); 2, part of cephalic capsule showing the antennae, mandible and maxillary palpi (ANT: antennae; MD: mandible; MP: maxillary palpi); 3, posterior end of the larva in lateral view; 4, posterior end of the larva in dorsal view; 5, posterior end of the larva in ventral view. Scale bar 1, 3, 4, 5: 1 mm. Scale bar 2: 0.1 mm

FIGURES 6 – 11. Dasybasis (D.) pruinivitta (Kröber), pupa. 6, general aspect of pupa in lateral view (ABS: abdominal spiracle; AMS: anterior mesonotal setae, PS: pleural setae; THS: thoracic spiracle); 7, frontal plate in anterior view; 8, frontal plate in ventral view (ANT: antennae; AOS: anterior orbital setae; CT: callus tubercle; pos: posterior orbital setae); 9, thoracic spiracle in lateral view; 10, anal segment in lateral view (DT: dorsal tubercle; LT: lateral tubercle; VT: ventral tubercle). (11) anal segment in posterior view. Scale bar 6, 7, 8, 9, 10, 11: 1 mm. Scale bar 7: 0.5 mm.