A NEW SPECIES OF VIETNAMELLA FROM CHINA (EPHEMEROPTERA:EPHEMERELLIDAE)
YOU DA-SHOU SU CUI-RONG(Nanjing Teacher's University)
The genus Vietnamella was first erected by Russian Ephemerologist Tshernova (1972) who described 3 nymph specimens from Vier nam and designated as Vietnamella thani. Recently we found 7♂♂ 11♀♀from Sangang of Fujian Province on June 1982 and many males and nymphs from Zhu Fo An of Dabieshan Mountains on June 1983, from Da Hua Ping,Qi Lin, Banzhu Yuan of Dabieshan Mountains on July 1983. These specimens belong to be a new species, and we describe male and female and nymph as follows:Vietnamella dabieshanensis sp. nov.Male imago (in alc.) Male specimen being very similar to Ephemerellina. Length of body 16 mm, wing expension 34 mm. 2 compound eyes contact at the middorsal line. Fore thorax light brownish in color. Fore wing transparent and glistering, with many cross veins. In the front angle of area the cross vein divided into 2 lines, MA forked, Imp with 3 veins Hind wing comparatively smaller, round in shape, MA not forked, Cu1, Cu2, 1A parallel progressed. Fore leg browish yellow in color, the proportion of femur, tibia and tarsus of fore leg being 3.16:4.67: 3.90. Tarsal joints rank 2, 3, 4, 5, 1 The proportion of femur, tibia and tarsus sfhind leg being 3.79:2.76:0.82 The tarsal joints rank 4:1 = 2 = 3. Porceps 3 segmented, the first and secend segments almost equal in length, the 3rd segment rather small, penial lobes fused, with its apical portion separate and chitinized.Female imago (in alc.) Length of body 17mm wing expension 38 mm. Two compound eyesfar apart. The distance between 2 eyes =1 3/4 tims the diameter of a single compound eye, Tho-4rax and abdominal segments having 2 different colors, deeper or lighter. In the deeper type the costal vein, costal area and subcostal veins are coffee color. Both tarsal joints rank 4:1 = 2:3. The lateral side of both 9th and 10th abdominal segments produced a longitudinal ridge, getting sharp at the rear end. Eggs small, elliptical, with a triangular lip at the ant. end.Male subimago (in alc.) Smaller, length of body 13 mm., wing expension 22 mm. Compound eyes and wing venation similar to adult male. The middle thorax pale white in color, with 3 pieces of gray markings. Tibia of fore leg longer than femur and tarsus. The tarsal joints rank 5, 2, 3, 4,1 The femur of the hind leg longer than tibia tarsus. The tarsal joints rank 4:1=2:3. Forceps 3 segmented, penial lobes short and straight, 2 penial lobes not entirely fused with a longitudinal groove in between.Nymph (in alc.) There are 3 pairs of occipital-genal ridges on the head. On the outer side of antennae is a pair of straight angle. Mouth parts similar to V. thani. There is a tranverse row of minute setae on the labrum, right and left mandible not similar. maxillary palpus 3 segmented, its inner margin with 2 knife-shaped setae, lingula 3 pieces, the middle one broader, labial palpus short, generally not exceed the lateral edge of paraglossa. The femur of fore leg broader, its ant. edge with a line of 5-6 or 7-8 sharp teeth. Middle and hind legs normal. Along the lateral line of 1-10 abdominal segments is a pair of longitudinal ridge being sharp at its rear end. The foregoing characters similar to V. thani. From 2-7 abdominal segments there are 6 abd. lobes, each lobe with 3 yellow markings on the dorsal surface and 2 parallel lines of gills on the ventral side, the 6th abd. lobe with 2 dorsoventral lobe. These characters are different from V. thani. Middle caudal filament longer than the cerci. Length of body 15 mm., length of caudal filament 8 mm, black in color.