Tipula (Pterelachisus) pabulina Meigen, 1818

Podeniene, Virginija, Nasevičiene, Nijole & Podenas, Sigitas, 2019, Notes on the first instar larvae of the genus Tipula (Diptera: Tipulidae), Zootaxa 4567 (1), pp. 90-110 : 100-102

Tipula (Pterelachisus) pabulina Meigen

( Figs. 40–47 )

Examined material: 13 egg-larvae from female captured in Vilnius district, N54.68662, E25.30054, 19 V 2011, eggs were laid on 21 V 2011, egg-larvae hatched on 5 VI 2011; 1 egg-larva from female captured in Vilnius district, N54.68419, E25.29904, 19 V 2011 , eggs were laid on 23 V 2011, egg-larva hatched on 1 VI 2011.

First instar larva. Length 2.29–2.31 mm, width 0.44–0.45 mm. Body covered with pale microscopic hairs. Cuticle transparent.

Head capsule. Length 0.34–0.36 mm, width 0.22–0.23 mm. In general, very similar to that of T. (L.) vernalis . Differences were noticed in shape of hypostomium, mandible, antenna and arrangement of sensory structures on labrum. Hypostomium bears five sharp long teeth and shape of teeth differ from that of T. (L.) vernalis and other above mentioned species ( Fig. 40 ). Mandible generally very similar to that of T. (L.) vernalis and other above mentioned species, but shape and size of teeth slightly different ( Fig. 41 ). Shape of segment of antenna and size of apical papilla differ from that of T. (L.) vernalis and other above mentioned species ( Fig. 42 ). Labrum in general very similar to that of other known Tipula , but arrangement of setae differs from other above mentioned species: two medium long setae present on membranous part on both sides of labrum ( Fig. 43 ). Three medium long setae located on anterior part of labrum, one long and one short setae present on anteriolateral part of labral lobe, one long and one very short seta located on posterior part of labral lobe. Arrangement of setae on frontoclypeus similar to that of T. (P.) irrorata ( Fig. 35 ).

Thorax. Very similar to that of other known Tipula .

Abdomen. In general very similar to that of other known Tipula . Setae D4 and D5 the shortest. D1 and D6 are similar in length and just slightly longer than D4 and D5 ( Fig. 44 ). D2 and D3 the longest setae, they are twice as long as D4 and D5. D2–D3 and D5–D6 very close to each other. V1 absent ( Fig. 45 ). V2 the shortest. V4 almost twice as long as V2. V3 and V5 almost three times as long as V2. V4–V5 make pair and are very close to each other. L3 very short, L1 twice as long as L3. L2 and L4 very similar in length and three times as long as L3. Setae L1, L2, L3 very close to each other ( Fig. 46 ).

Spiracular disc. Spiracular field surrounded by four almost equal round-tipped lobes, which are flat and elongate ( Fig. 47 ). Lateral lobe 1.5 times as long as width at the base, partly (inner part) covered with dark elongated L-shaped sclerite, lower branch of sclerite extends almost to the center of spiracular field. Lobe bears four stout long bristles and one short bristle on the apex. Each long bristle slightly more than five times as long as the lobe. Length of short seta almost equal to the width of lobe at the base. Length of ventral lobe almost as width at the base, inner margin of lobe covered with pale moon-shaped sclerite. Tuft of five long setae located at the apex of lobe, two short setae present apically to it. Tuft of six medium long setae present on the inner margin of lobe (close to the base). Tuft of six medium long setae located on outer part of lobe (close to the base). Five tufts of different in length setae located above the each spiracle. Three the innermost tufts are close to each other and consists of four long setae each. Laterally from it two tufts of two short setae, which very close to each other. Spiracles large, circular and close to each other. Distance between them less than diameter of a spiracle.

Anal field. Anus surrounded by four short similar in shape and size, white and fleshy anal papillae. A few tufts of long setae present on anal segment.

Figures

FIGURES 40–47. Tipula (Pterelachisus) pabulina, first instar larva. 40: hypostomium; 41: right mandible; 42: right antenna; 43: general view of labrum; 44: dorsal abdominal setae (segments II–VII); 45: ventral abdominal setae (segments II–VII); 46: lateral abdominal setae (segments II–VII); 47: spiracular field.

FIGURES 31–39. Tipula (Pterelachisus) irrorata, first instar larva. 31: hypostomium; 32: right mandible; 33: right antenna; 34: general view of labrum; 35: frontoclypeal setae; 36: dorsal abdominal setae (segments II–VII); 37: ventral abdominal setae (segments II–VII); 38: lateral abdominal setae (segments II–VII); 39: spiracular field.