Nephrotoma dorsalis Fabricius, 1782

Podeniene, Virginija, Naseviciene, Nijole & Podenas, Sigitas, 2014, Notes on the first instar larvae of Ctenophora and Nephrotoma (Diptera, Tipulidae), Zootaxa 3764 (2), pp. 152-168 : 163-164

Nephrotoma dorsalis Fabricius, 1782

( Figs. 49–56 )

First instar larvae. Length 1.41–1.43 mm; width 0.31–0.32 mm. Body covered with pale pubescence. Cuticle is transparent.

Head capsule. Length 0.36–0.37 mm; width 0.15–0.17 mm. In general it is very similar to that of other Nephrotoma . Minor differences were noticed in shape of hypostomium, mandible, antenna. Hypostomium bears five blunt teeth. Shape of the outermost teeth is different from the others. There is a prominent incision on posterior part of hypostomium ( Fig. 49 ). Mandible in general is very similar to that of N. flavescens , but shape of teeth is slightly different ( Fig. 50 ). Antenna is very similar to that of N. pratensis , but N. dorsalis has more peg-like sensillae on the apex of basal segment ( Fig. 51 ). Labrum in general is very similar to that of N. crocata and N. pratensis ( Fig. 52 ).

Thorax. In general is very similar to that of other Nephrotoma species.

Abdomen. In general is very similar to that of other Nephrotoma species. Seta D1 is very short; D2 is long and six times as long as D1; D3 is the longest and eight times as long as D1 ( Fig. 53 ); D4, D5, D6 are very similar in length, three times as long as D1. Setae D2, D3 and D4, D5 make pairs and are very close to each other. Seta V1 is very short; V2 is the longest ventral seta and is ten times as long as V1 ( Fig. 54 ); V3 is eight time as long as V1; V4 is four times as long as V1. Setae V1, V2 and V3, V4 make pairs and are very close to each other. Lateral setae are arranged in a line. Setae L1, L3 and L4 are very similar in length and are three times as long as L2 ( Fig. 55 ). Seta L4 is most distant from the other setae.

Spiracular disc. Spiracular field is surrounded by four flat and elongate round-tipped lobes ( Fig. 56 ), which are covered by sclerites. Lateral lobe is prominent, its length almost 1.5x the width at the base. It has four long stout apical bristles. The length of each bristle is almost as long as one-fourth of the whole body. Two tufts, each consisting of two bristles, are located on dorsal margin. Lobe bears pale, stripe-shaped sclerite. Ventral lobe is almost as long as its width at the base. It has apical tuft of two bristles. Tuft of three long bristles is on inner margin; tufts of two short and two long bristles are on outer margin; a tuft of four long bristles is at the base. Lobe bears pale, wide leaf-shaped sclerite. Three tufts of long bristles are above the spiracles. The innermost tuft consists of two bristles; others consist of three bristles. Spiracles are large, circular and close to each other. Distance between them is smaller than diameter of a spiracle itself.

Anal field. Anus is surrounded by four long, cone-shaped, white and fleshy anal papillae. There are few long setae on anal segment.

Specimens examined. 23 egg-larvae from female captured near Lazdijai, N54.24060, E23.51560, 23 VI 2011, eggs were laid on 25 VI 2011, egg-larvae hatched on 14 VII 2011; 43 egg-larvae from female captured near Lazdijai, N54.24067, E23.51526, 23 VI 2011, eggs were laid on 24 VI 2011, egg-larvae hatched on 0 9 VII 2011; 110 egg-larvae from female captured near Lazdijai, N54.24072, E23.51560, 23 VI 2011, eggs were laid on 25 VI 2011, egg-larvae hatched on 18 VII 2011.

Figures

FIGURES 49 – 56. Nephrotoma dorsalis, first instar larva: 49. Hypostomium. 50. Mandible. 51. Right antenna. 52. General view of labrum. 53. Dorsal abdominal setae (segments II – VII). 54. Ventral abdominal setae (segments II – VII). 55. Lateral abdominal setae (segments II – VII). 56. Spiracular field.