４　Diamesinae
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Ｄｉａｍｅｓｉnae　 is classified into the following three tribes.

４-1 　Boreoheptagyiini　・・・・　Head capcel with one pair of tubercle. Abdominal segments with minute, closely set multi-pointed spines.
                                                        Posterior parapod bearing circles of claws.
                        　　　　　　　　　　　　　　　　Boreoheptagyia ( 1 genus , several species )
４-2 Protanypodini・・・・・・・・Head capsule with numerous ,multi setae. Postoccipital margin with a projection on each sides.

　　　　　　　　　　　　　　　　　　　　　　　　　　　　Protanypus　(1 genus, 1 species ?)
４-3 　Ｄｉａｍｅｓｉｎｉ　・・・・・・・・・Without above characteristic of Boreoheptagyiini and Protanypodini.
　　　　　　　　　　　　　　i　　　　　　　　　　　　Diamesa , 　 Pagastia ,　 Potthastia , 　 Pseudodiamesa , 　 Syndiamesa , Sasayusurika

　　　                                       Diamesinae Genus　ＤＡ

４−1　Ｂｏｒeoheptagyiini


Boreoheptagyiai

In the country , several kinds of Boreoheptagyia distributed.  They inhabit on the surface of stone or rock in fast stream.

Medium size larvae, 3〜6 mm, dark greenish brown〜dark brown in color.	Head blackish brown: 1 pair of tubercle.	Tubercle with much wrincle: 　Antenna with 5 segments, antennal ratio 1.4〜1.8. Ssegment 3 annulated.
Mentum trapezoid, 4 median teeth on surface and 5 or 6 pairs of lateral teeth on oblique sides.	Tubercle on head capsle long or short or absent.	Both Ｓ�Tand Ｓ�Usimple. pecten epipharyngis 5 broad , elongate , apically blunt scales.  Premandible with 10 teeth, lateral spine branched or plumose.
Mandible: apical tooth brown or light yellow.  4 inner teeth subequal. Seta interna consisting of 10〜16 simple weakly serrate branches.	Dorsum of thorax and abdomen with minute, closely set simple-, double- or multi-pointed spines usually forming regular patterns on thorax and 2 transvers bands on each abdominal segment.	Posterior parapods partly fused basally, each bearing circle of claws.
	・Tow pairs of anal tubules present, shorter than posterior parapods. ・Procercus very short or absent, 6 shot anal setae present.
		Procercus very short or absent.

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４-2 　Protanypodini
　Ｐｒｏｔａｎｙｐｕｓ

Body length 11〜12mm. Dorsal side is spotty pattern of light brown. They inhabit on the bottom of deep lakes (depthh of 50〜150m) in Touhoku district ,Lake Tazawa , Inawashiro　and Numazawa-Numa  The acidity of these lakes is comparatively hight 。

Postoccipital margin with a long, ventrolateral , posteriorly-directed projection on each sides.	Mentum: median teeth broad, middle 2/3 irregular, without teeth. Lateral teeth 4 pairs , 1st lateral tooth broad, 2nd 〜4th teeth pointed. Ventromental plate absent.	With 4 segments. about 1/6 length of head capsle. Antennal ratio 1.9〜2.0. Ring organ on basal 1/6 of segment 1. Segment 3 and 4 short. Segment 3 non annulate.
	S�Tbig and short, Ｓ �Uthin and short. Labral lamellae consisting of a semi-circular row of broad leaf-like. Pecten epipharyngis consisting of 3 serrated to point scales. Premandible narrow . straight with weak 2 inner teeth.　(see fig. below)
		1・Antenna 2：Mentum 3：Head: head capsule with   numerous closely -spaced    short setae. Eye spot 1 pair, large. 4：Projection on postoccipital margin. 5：Lubrum 6；Ｍ　appendage 7：Mandible 8：Maxilla 9：Tip of anterior parapod with     12rows of claws, each row     with 10 or mor claws. 10：Clwas of anterior parapod 11：Claws of posterior parapod 12：Anal tubules and posterior      parapod 13：Procercus height 2.5 times      of diameter , with 6 anal         setae
Apical tooth as long as 5 inner teeth.

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４-3 　Diamesini

Diamesa

About 20 species found in the country ewidely . Larvae inhabit on surace of rock in fast flowing water.

All the shape of Diamea larva. Body length 5〜9mm. Abdominal segments yellowish brown  Postccipital margin very strong Procercus reduced or absent, 4 anal setae short .	Mentum with one median tooth a little 〜a quite broad  and 8〜11 pairs lateral teeth	Mandible brackish brown whole, 1 apical tooth and 4 inner teeth　Ｓ�Tstrong and long simple.、Ｓ�Uthin and short simple. Pecten epipharyngis 5 elongate , helmet-shaped scales. Premandible with 7 teeth.,  lateral spine simple or branched.
	Antenna with 5 segments, segment 3 annulated. Antennal ratio 0.8〜1.8. Segment 3〜5  short.

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Pagastia

Large larvae ６〜１０mm. yellowish brown 〜brown . Larvae inhabit in the river bed of the folowing strem . About 20 species found in the country widwly.

Median tooth broad, irregular Lateral teeth ６〜９ pairs Ventromental plate large, overlap with lateral teeth	Antenna with 5 segments. Segment 3 annulated clearly. The formes of antanna ( antannal ratio, blade etc.) various ..	Ｓ�Tbroad, Ｓ�Uthin.  Pecten epipharyngis 3 elongate scales. Premandible spatula-shaped with 2〜3 teeth, lateral spine absent..
Pagastia classifiied into two types by form of mandible showing upper pictures.   Left picture: large apical tooth and one inner teeth brock consisting of 4 teeth.   Right picture: apical tooth and 4 inner teeth.		Premandile palmate with 6〜8 teeth , lateral spine simple or bifid.

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Potthastia

Genus Ｐｏｔｔｈａｓｔｉａ　with the following two type,　P. gaedii 　type and 　P. longimana　 type.

Potthastia gaedii type
Body length 3〜6mm.
Many species distribute widely in the country, live in algae grown at surface of stone, fast stream.
　

Eye spot 1 pair , large.	Median tooth occupies 1/3 of whole mentum, pale yellow Lateral teeth 7〜8 pairs.  Ventromental plate small , overlap with lateral teeth.	Antenna with 5 segments.  Antennal ratio almost 1.5〜2.0
	・Anal tubules spindle-shaped. ・Procercus small, as long as wide, with 7 anal setae.
Mandible with 4 inner teeth
Potthastia longimana type
Body length 4〜6mm , pale yellow. Head small, about 1/20 of body length. Eye spt 1 pair large. According to antenna ratio and form of premandible, P. longimana type is divided into several types. Distribute widely in the country.
mentum without median tooth and lateral teeth
	１：antenna : antennal ratio 0.5〜0.7. Segment 2 longer than basal segment. Segment 3                  annulated clearly.　 　２：mentum: without median tooth and lateral teeth,  whole mentum thin lamella like,  low convex.. 　３：Ｓ�T. Ｓ�U: thin needle loke. 　４：premandible: serrated with about 10〜20 teeth.　 　５：mandible; sharp apical tooth and sharp 3 inner teeth. 　７：anal tubules; dome shaped with several small projections around the tip of tubules. 　８：procercus long,  7 anal setae on the upper side of the procercus. 　９：Claws of anterior parapod　 　１０：Claws of posterior parapod: claws with small serrations.。
mandible and antenna

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Pseudodiamesa

Large size larvae, １０〜１２ｍｍ. Three kinds of the larvae of Pseudodiamesa in the country and one kind was caught in Kamchatka .They live in low temperature.

Three median teeth and lateral teeth belong to different plates. Lateral teeth 5〜6 pairs; 2nd teeth from outside larger than both side teeth. Ventromental plate overlap with mentum.	Premandible with 8〜10 teeth.,  lateral spin simple. Ｓ�T broad. , simple. Ｓ�U thin , simple.	Antenna with 5 segments; half of mandible: 3〜５ｔｈ segments short, 3rd segment annulated hard to visible. Mandible with 4 inner teeth.  Seta subdentalis short. Setae interna with 14〜16 simple.to weakly serrated branches.
	・Abdominal segments brown, spotted design. ・Head brown. Postoccipital margin strong , blackish brown. ・Eye spot small, 1 pair. ・Anal tubules 2 pairs; 1 par situate both sides of anus; the other pair upper and lower sides of anus. ・Out side of prosercus with or without a small projection.. Anal setae ７〜８.

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Syndiamesa

Large size larva up to 8 〜 10mm, pale greenish brown.
They live in mosses surface of rock in mountain stream.

Median tooth larger than 1 st. lateral tooth. Lateral teeth 10 pairs. The whole ventromental plate dark brown.	Pecten epipharyngis 5 strong scales. Premandible with 6〜7 teeht and 1 lateral spine .	Antenna with 5 segments, 1/6 times   of head capsle.  Antennal ratio 　  2.0〜2.3., Ring organ near the bottom end of basal segment.  Segment 3 anulated clearly.
	１：antenna ２：mentum ３：labrum: labral lamella apically divided into 10 or more teeth of comb-like.. Ｓ�T: long scale-shape . Ｓ�U: thin, needle like. ４：mandible blackish brown, 4 inner teeth. seta subdentalis short spine ５：ventral side of head blackish brown. ６：claws of anterior parapod with serrate ７：anal tubules short conical ８：claws of posterior parapod dark brown ９：procercus short , with 6 anal setae

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Sasayusurika　aenigmata 　
This larva found in Mimi-River ( Shiiba village , Miyazaki pref, Japan) only , lives in fast stream.

Median tooth as wide as 4 lateral teeth combined , yellowish brown. Lateral teeth 6 pairs, Ventromental plate broad.	Ｓ�T: slightly thick needle like . Ｓ�U: thin, long needle like. labral lamella lacking. Pecten epipharyngis 5 long scales . Premandible spatula shaped	mandible with 4 inner teeth.
Antenna with 5 segments, antenna ratio 0.9〜1.0. 　Segment 3 annulated , 1.8 times of segment 2. 　Blade extending to tip of segment 3.	・Basal part of ventral side of head blackish brown. ・Anal tubules are two pairs to the left and right of the anus , and 1 tubule under anus. ・Procercus short , with 8 anal setae.

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Diamesinae Genus DA 　(Sympotthastia?)
This larva was found in Utunai River (Hokkaido Shumarinai ), live fast stream.

	Diamesinae Genus DA (Sympotthastia ?) Antenna with 5 segments. Segment 3 annulated . Lauterborn organ lacking . Ｓ�T: thick needle like, Ｓ�U: thin short needle like. Labral lamella thin. Pecten epioharyngis heart shaped . Premandible :spatula shaped. Mentum: Median tooth wide , lateral teeth with 11 pairs

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