516 Mr. H. Campion on the Use of 



was the ^''two wiiig'd Ephemeron " which had flown'"' within 

 side^' his window, figured and described by Moses Harris in 

 1776, although no name was suggested for it at thaf time. 

 It was stated to expand about half an inch, and the figures 

 show it as a female sub-imago (Exposit. Eng. Ins, p. 21, 

 pi. vi. figs. 1 & 3). In 1834 John Curtis established the 

 genus Brachycercus for the reception of Harris's species,- 

 which he named Harrisella^ and two other British Mayflies, 

 chironomiformis, Curt., and minima^ Curt. (Lond. & Edinb. 

 Phil. Mag. ser. 3, vol. iv. p. 122). The insects to which these 

 names were applied are all females, and consequently have 

 very short setse. The fact that the corresponding males 

 have very long setse did not become known until many years 

 later. 



In 1836 J. F. Stephens brought forward his genus Ccenis, 

 which he divided into t^vo sections, the first, which he like- 

 wise called Canis, including two '' species '' ^' with the 

 filaments several times longer than the body '^ (that is, male 

 specimens), and the second, Brachycercus, Curtis, consisting 

 of five " species^' " with the filaments scarcely longer than 

 the body, or shorter, stout at the base" (females). The 

 species described in the section Ccenis were macrura, Steph., 

 and dimidiata, Steph., while those referred to Brachycercus 

 were brevicauda, '^ Fabr.,'' harrisella, Cnrt., pennata, Steph., 

 chironomiformis y Curt., and interrupta, Steph. (111. Brit. Ent. 

 Mand. vi. pp. 60-62). 



In the second edition of his ' Guide to an Arrangement 

 of British Insects,' column 164 (1837), Curtis enumerates, 

 under the same sectional headings, the same seven species 

 given by Stephens, but substituting his own name minima 

 for dimidiata, Steph. At the same time, he treats Cmnis as 

 a synonym of Brachycercus. The first species cited under 

 Brachycercus is again harrisellus, or, as he now writes the 

 name, Harrisii, and that this fact has the eff'ect of fixing 

 the genotype is evident from the following words, quoted 

 from the preface : — " It may often happen that all the 

 species following such generic names would not be con- 

 sidered by the Author who proposed the name as belonging 

 to his group, but the one immediately following is always a 

 typical species." According to the same authority, macrura^ 

 Steph., is the type of the section Ccenis. 



Another attempt to supplant Curtis's genus was made by 

 Burmeister, who erected his own genus Oxycypha, with 

 Brachycercus, Curt., as a synonym, for the three new species 

 O. lactea (^=^ Ccenis dimidiata, Steph.), 0. luctuosa (^=^ Ccenis 

 harrisella. Curt.), and O. discolor {= Trie or y thus discolor, 

 Burm.) (Handb. Ent. ii. p. 796 ; 1839). 



