Nephrotoma pratensis Linnaeus, 1758

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 : 160-162

Nephrotoma pratensis Linnaeus, 1758

( Figs. 41–48 )

First instar larvae. Length 1.75–1.85 mm; width 0.32–0.33 mm. Body covered with pale pubescence. Cuticle is transparent.

Head capsule. Length 0.38–0.39 mm; width 0.22–0.23 mm. In general is very similar to that of N. flavescens . Differences were noticed in shape of hypostomium, mandible, antenna and arrangement of sensory structures on labrum. Hypostomium bears five blunt teeth. There is a prominent incision on posterior part of hypostomium ( Fig. 41 ). Mandible in general is very similar to that of N. flavescens , but shape of teeth is slightly different ( Fig. 42 ). Basal segment of antenna is cone-shaped, but membranous apical part is much smaller than in N. flavescens ( Fig. 43 ). There are several small peg-like sensillae on the apex of basal segment. Labrum in general is very similar to that of N. crocata ( Fig. 44 ).

Thorax. In general is very similar to that of N. flavescens .

Abdomen. In general is very similar to that of N. flavescens . Setae D1 and D6 are the shortest. They both are of equal length. D2 is the longest among all setae. It is nearly seven times as long as D1 ( Fig. 45 ). D3 is twice as short as D2; D2 and D3 are very close to each other; D3 and D5 are very similar in length and are four times as long as D1; D2 and D3 are very close to each other. Seta V2 is very long; V1 is almost three times as short as V2 ( Fig. 46 ). Seta V4 is very short, half the length of V3 and less than 1/ 6x the length of V2. Setae V1, V2 and V3, V4 make pairs and are very close to each other. Seta L1 is as long as L4; both are three times as long as L2, which is the shortest lateral seta. Seta L3 is half the length of L1 ( Fig. 47 ).

Spiracular disc. Spiracular field is surrounded by four almost equal round-tipped lobes, which are flat and elongate ( Fig. 48 ). Lobes are almost as long as wide at the base. They have no sclerites. Lateral lobe has three long stout apical bristles, which are about six times as short as the whole body. On dorsal part it has two tufts, each consisting of two short bristles. Above the spiracles there are three tufts, each composed of two bristles of different length. The bristles of outermost tuft are the longest. Ventral lobe has apical tuft of three long bristles; tuft of two approximately equal in length bristles are located on inner margin; tuft of two short bristles present on outer margin and a long bristle, almost as long as lobe itself, is next to them. Tuft of three long bristles is at the base of ventral lobe. Spiracles are large, oval 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 a few long setae on anal segment.

Specimens examined. 229 egg-larvae from female captured in Vilnius, N54.68263, E25.24766, 15 V 2011, eggs were laid on 17 V 2011, egg-larvae hatched on 31 V 2011; 182 egg-larvae from female captured in Vilnius, N54.68419, E25.29904, 19 V 2011, eggs were laid on 21 V 2011, egg-larvae hatched on 0 2 VI 2011; 45 egg-larvae from female captured in Vilnius, N54.68662, E25.30054, 15 V 2011, eggs were laid on 28 V 2011, egg-larvae hatched on 0 8 VI 2011; 317 egg-larvae from female captured in Naujoji Vilnia environs, Vilnius district, N54.70365, E25.40598, 22 V 2011, eggs were laid on 26 V 2011, egg-larvae hatched on 17 VI 2011; 10 egg-larvae from female captured in Naujoji Vilnia environs, Vilnius district, N54.70365, E25.40598, 11 VI 2011, eggs were laid on 14 VI 2011, egg-larvae hatched on 0 5 VII 2011; 132 egg-larvae from female captured in Naujoji Vilnia environs, Vilnius district, N54.70365, E25.40598, 19 V 2012, eggs were laid on 20 V 2012, egg-larvae hatched on 27 V 2012.

Figures

FIGURES 41 – 48. Nephrotoma pratensis, first instar larva: 41. Hypostomium. 42. Mandible. 43. Right antenna. 44. General view of labrum. 45. Dorsal abdominal setae (segments II – VII). 46. Ventral abdominal setae (segments II – VII). 47. Lateral abdominal setae (segments II – VII). 48. Spiracular field.