214 STtlATlOMYID.^. 



This genus may be easily recognised amongst British species, even if 

 Actina nitens witli its hairy eyes should occur, but its relationship to 

 Beris Morrisii is very obvious, as that species often has a small incomplete 

 third veinlet from the discal cell, almost bare eyes (scarcely touching 

 in the male), small but evident palpi, and a pale -haired thorax in both 

 sexes. The characters given here for the genus may be too limited, as they 

 are mainly drawn from the European C. tihialis. 



The metamorphoses are well known, as Handlirsch in 1883 gave a 

 detailed description with figures ; he found the larvse in mouldering wood- 

 earth which contained decaying vegetable matter. 



Chorisops (including Exaireta) is recorded from Euiope (one species 

 only), North and South America, Australia, and New Zealand. 



¥iG.lhl.— Chorisops tibialis i. x 12. 



Synonymy. — I have dealt with the synonymy of the European genera Beris, 

 Actina, and Chorisops in my synonymical note under Beris, but I made no reference 

 there to the genus Exaireta of ScMner (1867), amended by Osten Sacken in 1878 to 

 Neoexaireta on the ground of preoccupation ; a close examination of various species 

 of Exaireta confirms me in the belief that it cannot be separated from Chorisops, 

 and in fact Exaireta {Beris) luteipennis Philippi from Chih is extremely closely 

 allied to our European C. tihialis. Nowicki's argument upon the synonymy of 

 Exaireta Schin. and Diphysa Macq. is well grounded, but he is wrong in stating 

 that the veinlet (= upper branch of postical vein) which separates (what ought to 

 lie) tlie fourth posterior cell from the fifth springs from the discal cell in Beris, but 

 from the second basal cell in Exaireta, as I cannot find any more distinction between 

 Exaireta (including the type species E. spinigera Wied,) and Beris than I can 

 between Chorisops and Beris. As both the names Exaireta and Diphysa are pre- 

 occupied, the only change required in the present synonymy is to sink Neoexaireta 

 under Choriso2)s. I am aware that Brauer in his paper on the JVotacantha in 1882 

 separated these two genera, but I do not think his distinctive characters of generic 

 value, and his cursory work was proved by his erroneous spelling Chlorisops. All 

 these writers seem to have overlooked Rondani's paper in 1863 (Archiv. p. Zool. 

 Modena, iii. 87) in defence of his genus Chorisops, in which he gives the European 

 C. tibialis as the type species but states that the genus includes '' exoticse nonnullge, 

 " Servillei — Javana — Macq. etc.," though all knew that Beris Servillei Macq. was a 

 synonym of E. spinigera Wied, which was the type species of Exaireta. Curtis and 

 Haliday were wrong in considering C. tihialis to be the type of the genus Actina 

 because that species was not described until seventeen years after the genus Actimi 

 had been founded, but that question is also dealt with in my synonymical note upon 

 the genus Beris. 



1, 0. tibialis Meigen. Abdomen more or less yellow on the disc. 

 Scutellum with yellow spines. Eyes bare and well separated in both sexes. 



Easily distinguislied from the other BerincB by the yellowish 

 scutellar spines, and usually by the pale abdominal markings. 



$. Frons (fig. 152) shining bluisli black or dark green, about one-eighth the 

 width of the head at the vertex but gradually narrowing until below the 

 ocelli, and thence almost parallel-sided to the glistening white space just 



