肛脊摇蚊属二新种(双翅目:摇蚊科)

TWO NEW SPECIES OF MESOSMITTIA FROM CHINA (DIPTERA: CHIRONOMIDAE)

肛脊摇蚊属Mesosmittia Brundin,1956为直突摇蚊亚科Orthocladiinae的一个小属,与Camptocladius V.D.Wulp和Pseudosmittia Goetghebuer近缘,其主要特征为:复眼光裸;触角第2、3及13鞭节生有叶状感觉毛;翅无大毛,腋瓣缘毛少;肛尖退化。

Two new species of Mesosmittia Brundin are described in this paper. The type specimens are kept in the Biology Department of Nankai University.Mesosmittia dolichoptera Wang et Zheng, sp. nov. (fig. 1)Imago male: Dark brown. Total length about 1.8 mm. Flagellomeres Ⅱ, Ⅲ and Ⅷ with 3 sensillae chaeticae. AR 1.09.Acrostichals 11, dorsocentrals 7 on each side, prealars 3 on each side. Humeral pits small. Wing length 1.35mm. Total length/wing length about 1.44. Apex of R2+3 ended at apex of R4+5. Squama with 3 setae. LR1 0.45, LR2 0.39, LR3 0.56. Hypopygium as in fig. 1c.Holotype (?) & paratypes 5(?), Jilin Province (Changbai Mountain) 1986. Ⅵ. 23.Close to M. pairihortae Saether, 1985 in hypopygium form, but markedly differs from it in body length/wing length and AR values, etc.Mesosmittia yunnanensis Wang et Zheng, sp. nov. (fig. 2)Imago male: Black. Total length 2.43mm. AR 1.36.Acrostichals 12, dorsocentrals 8 on each side, prealars 5 on each side. Wing length 1.62 mm. Total length/wing length 1.5. Costa far extending beyond R4+5, extension distance about 140 μm. Squama fringe 5-6. LR1 0.49, LR2 0.41, LRs 0.52. Hypopygium as in fig. 2c.Holotype (?) & paratype 1(?), Yunnan Province (Yiliang), 1986. V. 25.Close to M. truncata Saether, 1985 in having very long costal extension and sub-rectangular virga, but differs from the latter in lacking of long setae on both side of the ridge of abdominal tergum IX, larger body size, much larger AR, black coloration and different inferior volsella.