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IX. Nr7v species of Ephemeridfe from the Tenasserim 

 Valid/. By the Rev. Alfred E. Eaton, M.A., 

 F.E.S. 



[Read March 9th, 1892.] 



The rule that description and naming of new species of 

 May-flies, represented incompletely by no matter how 

 many specimens of one grade or sex only, ought never 

 to be practised if the S2:)ecies lack definite character 

 with regard to that grade or sex, does not apply to 

 species of peculiar mark such as are distinguished in 

 the following pages. Considerable interest attaches to 

 them in respect of the geographical distribution of 

 genera, and some of the flies are particularly orna- 

 mental. They were collected in the Tenasserim Valley 

 by Mr. Doberty, and sent by him to Mr. R. McLachlan, 

 F.Pt.S. The specimens, 21 in number, represent eight 

 named genera, each (with one exception) by single 

 species. A key to the genera and larger divisions of 

 recent Ephnnerida is given in Trans. Linn. Soc. Lond., 

 2nd ser., Zool., vol. 3, part 5, p. 309, &c., preceded by 

 geographical notes. 



1. Ephemera pidcherrima, sp. nov. 

 Suhimago {dried), J . — A yellowish species with linear longi- 

 tudinal abdominal markings, besides a round spot just above the 

 pleura on each side of the 2nd segment ; also with an angulated 

 spot on the hind coxa ; and with three round or oblong spots in 

 the area immediately posterior to the submarginal area of the fore 

 wing. Hind wing spotless. Wings very light yellow ochraceous, 

 subopaque : fore wing sparsely marked with small violet-black 

 spots, situated — one each at the bulke of the siibcosta and radius, 

 one in line with these on the sector, a small one occupying the axil 

 of the fork of the praBbraehial nervure, and three others, one in the 

 middle of each of the last three cross veinlets immediately pos- 

 terior to the radius ; hind wing spotless, unicolorous. Neuration 

 in both wings concolorous with the membrane (but opaque), ex- 

 cepting a few cross veinlets in the submarginal area of the liind 

 , TRANS. ENT, SOC. LOND. 1892. — PART II. (jUNE.) 



