Aquatic Insects of Michigan by
Ethan Bright, Museum of Zoology Insect Division and School of Natural
Resources and Environment |
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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; R
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. 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 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,
Hypopygium. Ab9 tergite with 2
dorsal projections. Anterior projection 18-20 µm 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)
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