Nilothauma Kieffer

Key to male imagines

Key to pupae

Key to fourth instar larvae

Descriptions

Nilothauma babiyi (Rempel), 1937

Male Imago: (n = 9-12 except when otherwise stated). Total length 2.88-5.07, 3.57 (7) mm. Wing length 1.43-2 74, 1.95 mm. Total length/wing length 1.38-2.03, 1.80 (7). Wing length/length of profemur 2.22-2.74, 2.40. Head and thorax yellowish brown to with some light green markings; with a brownish mark across the mesopleuron beneath the wing; abdomen fuscous green to dark brown. Legs brownish stramineous, apex of fore femur and base and apex of fore tibia slightly darker brown. Head. AR 0.16-0.32, 0.25. Thirteenth flagellomere 113-298, 213 µm long. Temporal setae 6-9, 7; including 2 inner verticals; 2-4, 3 outer verticals; and 2-3, 3 postorbitals. Clypeus with 10-22, 14 setae. Tentorium 110-158, 127 µm (7) long; 14-22, 17 (7) µm wide at the sieve pore, 10-18, 14 µm (7) at the posterior tentorial pit. Stipes 102-172,126 µm (5) long; 16-20, 18 µm (5) wide. Palpomeres lengths (in µm): 26-54, 37; 30-54, 41; 58-98, 78; 98-172, 142; 100-214, 166. Third palpomere with 2 sensilla clavata, longest 12-24, 20 µm. Thorax. Dorsocentrals 7-18, 14; prealars 2-3, 2. Scutellum with 2 setae. Wing. VR 1.36-1.59, 1.47. Brachiolum with 1 seta; R with 14-20,17 setae; R1 with 10-16, 12; and R4+5 with 9-25, 17; remaining veins bare. Legs. Spur of front tibia 50-80, 62 µm long, including scale of 18-40, 27 µm long; spurs of middle tibia 26-40, 30 µmincluding 14-26, 20 µm long comb; hind tibia with 2 spurs 24-44, 30 and 24-46, 35 µm long, combs each 14-30, 22 µm long. Width at apex of front tibia 41-74, 54 µm; of middle tibia 43-74, 55 µm; of hind tibia 48-86, 62 µm. Sensilla chaetica 2-3 at 0.28-0.74 (6) of ta, of middle leg. Lengths (in µm, n = 6-11) and proportions of legs:

Hypopygium. Tergite IX with one dorsal projection on posterior margin of anterior tergal band, 21-58, 36 µm (7) long; 7-26, 16 µm (7) wide at base; 7-22,14 µm (7) wide at apex, with 4-12,7 (7) simple, apical setae, 52-72,61 µm (6) long. Anal point narrow and tapering, or slightly widened medially, but not spatulate, 42-58, 49 µm (8) long; 8-12, 10 µm (8) wide at base; 4-7, 5 µm (8) wide at apex. Phallapodeme 76-118, 89 µm (8) long. Sternapodeme thickened medially, but without median elongation. Tergite IX with about 7-14, 10 apical setae; laterosternite IX with 2-3, 3 setae. Gonocoxite 104-154, 126 µm (8) long. Gonostylus 140-230, 179 µm (8) long, 5-7 distal-median setae split at apex. Superior volsella club-shaped with 3 long setae, 38-126, 65 µm (8) long, covered with microtrichia; median volsella digitiform, apically split, 14-22, 16 µm (8) long with 3 or occasionally 2 long setae; inferior volsella narrow, 71-138, 97 µm (8) long, with microtrichia and 6-8 apically split setae at apex. HR 0.57-0.85, 0.71 (8); HV 1.61-2.28, 1.97 (7).

Pupa (n = 1-2). Total length about 3.3 1-3.35 mm. Exuviae pale with cephalothorax and caudal spur yellowish brown. Cephalothorax. Frontal setae short 24 µm long.
Thoracic horn apparently of 5 or 6 slender filaments, one of them with spines, longest filament apparently up to 280 µm long. Diameter of basal ring 19 µm. Other details not visible. Abdomen. Shagreen and chaetotaxy as in generic diagnosis. Ab2 tergite with 30-47 caudal hooklets. Posterior area of Ab3 and 4 tergites and
conjunctives 3/4 and 4/5 each with 6-7 rows of spinules. Pedes spurii B absent on Ab2. Ab8 with anal comb consisting of one main spur 34-41 µm long; distinctly separate outer lateral spur 19-23 µm long; separate median spur 11-15 µm long, basal spur on main spur present and 9 µm long or absent. Anal lobe 170-180 µm long; 30 taeniae on each lobe. Genital sac of male surpassing apex of anal lobe by 113-154 µm.

Fourth Instar Larva.(n = 5 except when otherwise stated). Total length 4.37-6.99, 5.07 mm. Head capsule 0.31-0.45, 0.39 rnm long. Postmentum 178-251, 210 µm (4) long. Head. Antenna (as in figure). Length of antennal segments (in µm) 28-36, 32; 11-14, 13; 4-7, 6; 8-17, 13; 5-7, 6; 1-4, 2. AR 0.74-0.93, 0.82. Basal antennal segment 12-17,14 µm wide; blade 24-28 µm (3) long; accessory blade not measurable. Premandible 39-50, 44 µm long. Mandible 88-128, 110 µm long, apical
innertooth directed distally, dorsal tooth present. Mentum 57-83, 70 µm wide, middle part about 10 µm wide. Abdomen. Anal tubules 71-113, 93 µm (4) long. Procercus 15-23, 20 µm high; 11-17, 16 µm wide; with 6-7 anal setae, 319-713, 507 µm long. Supraanal seta 206-563, 356 µm long; 0.64-0.79, 0.69x as long as anal setae.

Nilothauma bicorne (Townes), 1945

Male Imago (n=3, except when otherwise stated). Total length 1.82-1.91 mm (2). Wing length 1.02-1.13 mm. Total length / wing length 1.65-1.69 (2). Wing length / length of profemur 2.24-2.47. Colouration: Head and thorax yellowish brown with green markings, with a brownish mark across mesopleuron beneath wing; abdomen dark pea green. Legs brownish stramineous, apex of front femur and base and apex of front tibia slightly dark brown. Head. AR 0.16-0.18. Thirteenth flagellomere 84-104 µm long. Temporal setae 6 (2), including 2 inner verticals, 2 outer verticals,
and 2 postorbitals. Clypeus with 13-17 setae. Tentorium 82-94 µm long, 12-14 µm wide at sieve pore, 10-12 µm wide at posterior tentorial pit. Stipes 86-110 µm long, 4-8 µm wide. Palpomeres lengths (in µm): 22-28, 26-28, 50-56, 88-96, 116 (1). Third palpomere with 2 sensilla clavata, longest 14-20 µm. Palpomere lengths (in µm): 22-28, 26-28, 50-56, 88-96, 116 (1). Thorax. Dorsocentrals 7, acrostichals
10, prealars 2. Scutellum with 2 setae. Wing. VR 1.49-1.57. Brachiolum 0-1 seta, R with 12-16 setae, R1 with 4-5 setae, R4+5 with 12-15 setae, remaining veins bare.
Legs. Spur of front tibia 38-50 µm long including scale of 20-28 µm; spur of middle tibia 28-30 µm long including 18-20 µm long comb; hind tibia with 2 spurs each 26-28 including 18-20 µm long combs. Width at apex of front tibia 30-34 µm, of middle tibia 36-38 µm, of hind tibia 40-42 µm. Sensilla chaetica 1 at 0.70-0.81 of ta, of middle leg.

Hypopygium. Ab9 tergite with 2 dorsal projections. Anterior projection 18-20 µm
(2) originating from anterior tergal band, 22-44 µm (2) long, 10-12 µm (2) wide at base, 6-12 µm (2) wide at apex; apical setae 18-22 µm long, apically plumose. Posterior projection 40 µm (2) from anterior tergal band, 50 µm long, about 22 µm wide at base, 4 µm wide at apex; with 12 setae 8-18 µm long. Anal point 34-38 µm (2) long, 8-12 µm wide at base, 14-16 µm wide in middle; lanceolate, widest medially, apically subacute. Phallapodeme 40-52 µm (2) long. Sternapodeme medially rounded with an anteromedian knob-like projection. Laterosternite
IX with 3 setae. Gonocoxite 68-70 ptn long with 3 setae along inner margin. Gonostylus 108-110 µm (2) long, equally wide for most of its length; 5 distal-median setae, 4 ofthem apically split. Superior volsella 30-32 µm long, with basal-lateral spine, 1 long dorsolateral seta and 8-10 short marginal setae at apex, without microtrichia; median volsella 10-14 µm (2) long with 2-3 apical setae, bare, one of the volsellae partly divided; inferior volsella 54-60 µm (2) long, microtrichiose, with 6 apical setae, some split at tips. HR 0.62-65 (2), HV 1.69-1.74.

Pupa (n = 1-2). Total length about 2.7-2.8 mm. Exuviae pale with cephalothorax and caudal spur pale yellowish brown. Cephalothorax. Thoracic horn apparently of 5 slender, equal-sized filaments, each apparently up to 940 µm long. Other details not visible. Abdomen. Shagreen and chaetotaxy apparently as in generic diagnosis. Ab2 tergite with about 32 caudal hooklets. Ab8 with anal comb consisting of 3-4 spurs; anterior 1-2 spurs 8-15 µm long; median spur 17-23 µm long; posterior, main spur 30 µm long. Anal lobe 146 µm long, 34-36 taeniae on each lobe. Genital sac of male surpassing apex of anal lobe by 90 µm . Other details not measurable.

Fourth Instar Larva (n = 6-8, except when otherwise stated). Total length 2.55-5.10, 4.15 mrn. Head capsule 0.25-0.29, 0.27 mm long. Postmentum 116-169, 144 µm long. Head. Antenna placed on a about 25 µm high base. Length of antennal segments (in µm) : 17-28, 21; 8-14, 12; 4-5, 5; 7-13, 10; 4-6, 5; 1-2, 1. AR 0.54-0.80, 0.67. Basal antennal segment 8-14, 10 µm wide; ring organ 11-19, 15 µm from base; blade 19-28, 24 µm long; accessory blade 9 µm (2) long. Apical style of second segment 4-5, 4 µm long. Premandible 26-40, 30 µm long; with 2 apical and 2 basal teeth. Mandible 59-84, 71 µm long, apical inner tooth directed distally, dorsal tooth present. Mentum 36-52, 45 µm wide, middle part consisting of 4 teeth which may be worn down to appear as single, low median tooth. Ventromental plates with about 50 striae in basal 1/2. Abdomen. Anal tubules bulbous; longer pair 71-109, 91 µm (4) long; shorter pair 38-56 µm (3) long. Procercus 11-19, 15 µm (4) high; 11-15, 14 µm (4) wide; with 6 anal setae, 394-544, 453 µm long. Supraanal seta 289-450, 365 µm (5) long; 0.67-0.96, 0.78 (5) x as long as anal setae.

References

Adam JI, Sæther OA. 1999. Revision of the genus Nilothauma Kieffer, 1921 (Diptera: Chironomidae). Entomologica scandinavica Supplement 56:1-107.

Page created: Sunday, February 19, 2006 - Last updated: March 29, 2006 (EB)