２-3-3 Polypedilum group

（median teeth of mentum 2 or 4 , antenna with 5 segments）　
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　return to ３−３　Chironomini

　　　　　Polypedilum 　　Endochironomus 　　Ｐｈａenopsectra　　　Ｓｅｒｇｅｎｔｉａ　　Lipiniella
　　　Pedionomus 　　　Nilothauma 　　　　　Stenochironomus

Ｐｏｌｙｐｅｄｉｌｕｍ

Many spacies inclued in this Genus. Therefore very various the form. I have gotton 60 or more sample of Polypedilum.
Body color pale orange 〜dark red. Body length 5〜10 mm. Eye spot 2 pairs.

	4 medianteeth, center 1pair larger than outer 1 pair: Outer pair teeth smaller than 1st. lateral tooth. Lateral teeth 6 pairs.（above fig. left）: In Pedestre type , center teeth tallest.（P. pedestre type 　　.above fig. right) In many cases Ventromental plate fan shape, widely separated in the middle. As rarely , elongated, overlap slightly at the center ( show below fig.). Although Lateral teeth almost 6 pairs, also rare 5 pairs.
Antenna with 5 segments. Antenna ratio different depending on the spacies. Lauterborn's organ on the apex of segment 2, but in P.nubifer type ,each one on the apex of segment 2 and 3. ( fig. above center)		P. kamotertium　: head pear-shape. Form of basal segment of antenna, ventromental plate, anal tubules etc. are different from other Polypedilum.
The most common Polypedilum:: ・　Ｓ�T: plumose, edge of apex with small many teeth ・　Ｓ�U: apex edged with fine hairs. ・Pecten epipharyngis divided into 3 blocks, each block with several teeth. ・Premandible with 3 teeth.
	A kind of Polypedilum ? Characteristic by mentum , ventromental plate, mandible. (found in Lake Ikeda. Kagosima pref.)

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Ｅｎｄｏｃｈｉｒｏｎｏｍｕｓ

One species only found in River Kushiro.

Inner 2 teeth of median teeth semi-fused. Lateral teeth with 6 pairs. Medianteeth situated different plate from lateral teeth.	Ｓ�Ttriangular wing-shape , wedge with small comb like. Labral lamella wide umbrella shape . Pecten epipharyngis 3 blocks ,each with 3 pointed teeth.	Antenna with 5 segments.
		・This larva found in Kusiro river, live in nomal current, pebble bottom. ・body length10〜11mm, red, with 2 pairs eye spots slightly separate. ・Dorosal tooth of mandible small, yellowish brown. inner teeth 3, seta subdentalis thin, long, sharp. ・Anal tubules both 2 pairs oval ・procercus flat, anal setae 8 .

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Ｐｈａｅｎｏｐｓｅｃｔｒａ

This larva found in Lake Biwa, in pebble bottom.

center 1 pair of median teeth shorter than outer pair. Median teeth situated on diffrent plate from lateral teeth. Lateral teeth with 6 pairs, 1st lateral tooth small. Ventromental plate fan shape, radial line clear.	Inner teeth 3, seta subdentalis thin, sharp.
	・body length 7〜8mm ・antenna with 5 segments antenna ratio: 1.1〜1.2 ・Ｓ�T: plumose, edge with about 10 teeth of comb like. Ｓ�U: long, tip with comb like teeth . ・pecten epipharyngis : divided into 3 block, center block with 3 teeth, side with 4 teeth. ・premandible with 3 teeth. ・anal setae 8	difference with Ｓｅｒｇｅｎｔｉａ Phaenopsectra Sergentia median tooth of mentum inner pair small 4 teeth same size inner teeth of mandible ３ ４ premandible ３ ２〜４

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Ｓｅｒｇｅｎｔｉａ

Disteributed widely in Japan.. 4 species found .

4 median teeth almost the same size., median teeth situated on different plate from lateral teeth. Lateral teeth 6 pairs.。	antenna with 5 segments . mandible with 4 inner teeth .。	Although Sergentia has a similar morphlogical characteristics with Phaenopsectra, there are defferences at mentum and mandible. Premandible with 2〜4 teeth.

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Ｌｉｐｉｎｉｅｌｌａ　moderata

These larvae found in Lake Biwa (noth basin) and Yasu Liver ( flow into Lake Biwa)

Body length 4.5〜5mm. pale orange. Anterior parapods large, the same size as head.	Median tooth divided into 4, Lateral teeth 6 pairs. Ventromental plate elongate, both touch at center.	Dorsal tooth of mandible small, yellowish brown. Apical tooth large , inner teeth 3. Outer edge of mandible with 1 projection. Antenna with 5 segments.
Ｓ�T: plumose, rough serrated . Ｓ�U: thick needle like. Labral lamella wide umbrella shape. Pecten epipharyngis with about 20 irregular teeth.	1 pair ventral tubules on segment 11. Anal setae 7.

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Pedionomus

These larvae are found in Pond Hime( Hokkaido, Risiri Iland) and River Kusiro.

2 medianteeth slightly larger than lateral teeth. Lateral teeth 7 pairs. Ventromental plate elongated fan shape , radial lines uncler.	Antenna 5 segments, antenna ratio 　　1.3〜1.5.	Ｓ�T: plumose, rough serrated. Ｓ�U: strong, long needle like. Pecten epipharyngis divided into 3, each with 3〜5 teeth. Premandible with 3 teeth.
	Pedionomus Body length ５〜８mm. pale〜dark red. Eye spots 2 pairs nearly. Anal setae 8.

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Ｎｉｌｏｔｈａｕｍａ

These larvae are found in Pond Akan Onneto(Hokkaido), River Yasu( Shiga pref.) etc.

Median teeth of mentum 4 small . Lateral teeth 6 pairs. Ventromental plate large fan shape, radial line clear basaly.	Antenna : segment 3 shorter than segment 4. Lauterborn organ lacking. Style at the apex of segment 2 long.	Apical tooth of mandible especially long, bend sharply, pale yellow. 4 inner teeth short, brown. dorosal tooth lacking.
	Bbody length ４〜５ｍ. pale orange, head pale yellow. eye spots with 2 pairs. ・Ｓ�T: 3 〜5teeth . Ｓ�U: thick, long needle like,. lablal lamella apron shape . edge serrated ・Pecten epipharyngis 3 lobes, 　　　　 premandible with 3 teeth ・anal tubuls 2 pairs, long conical. ・procercus short, anal setae 7〜８

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Stenochironomus

Stenochironomus distrbuted in a fairly wide range in the country ,at least 2 species found

Mentum : 10 teeth arranged in shallow U-shape, the most outer lateral tooth small. Ventromental plate lacking or vestigial. 。	Antenna with 5 segments, Lauterborn organ lacking, accessory blade present.	Mandible triangular, upper half blackish brown. Drosal tooth large, situated so as to overlap between apical tooth and inner teeth.
Anal tubules baloon shape , lager than posterior parapod. Posterior parapods short, situated under segment 12。	Body length ７〜８ｍｍ.pale orange. with 2 pairs eye spots. Head in the flat, square ,1/20〜1/25 of body length. In spite of 1st. segment of thorax, all body thin. 。	Ｓ�T、Ｓ�U both several rough serrated. Labral lamell 2 lobes with serrated. Premandible with 3〜4teeth. 7 anal setae shot ..

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