I9I4-] E. Brunetti : Review of Genera in Culicidac. 



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because it is less amenable than other characters to the micro- 

 scopic differences that cuhcidologists delight in, but which, never 

 theless, have no real specific value in nature. 



Theobald in fact sa3^s (Mcno]^. iv, 381) after mature delibera- 

 tion " the venation is too variable to take with any degree of 

 seriousness." The truth is, that whilst of all taxonomic charac- 

 ters in Culicidac the venation, speaking broadly, is by far the most 

 uniform, a single typical form continuing through the family with 

 but two or three minor modifications, affording no opportunity to 

 found thereon a multiplicity of genera, yet it has both in the 

 species and in the individual a sufficiently wide variation to have 

 precisely the same restraining effect as regards species and varie- 

 ties. 



As regards modification, first there is the exact position of the 

 posterior cross vein in Mttcidus, which, theoretically, is beyond, 

 even if only sHghtly , the anterior cross vein. This would be a 

 good character if constant (always allowing for individual aberra- 

 tion), but in one or two species {alter nans and sudanensis) this 

 cross vein is evidently so little beyond the anterior cross vein as 

 to discount the generic value of the character. In Trichoprosopon 

 the two cross veins are theoretically in a line, but the genus is suffi- 

 ciently differentiated by the scaled metanotum. 



In Tipulidae and many families of Brachycera the posterior 

 cross vein is (generically) as often beyond as before the anterior 

 cross vein whilst very many genera have them practically in a line 

 with one another, the presence or absence of a discal cell between 

 them, of course, making no morphological difference. 



The validity of Mucidus on the position of the posterior cross 

 vein alone is precarious, but the genus seems to be substantiated 

 by the peculiar nature of the scales. 



The second modification is the shortened ist submarginal and 

 2nd posterior cells (called by culicid writers the '' forked cells") ' 

 in certain genera, one of the principal characters of the Megarhini 

 being the shortness of the forked cells, especially the ist submar- 

 ginal, while Theobald would distinguish his subfamily Urano- 

 taeninae by the very small ist submarginal cell. 



As regards the generic value of the short forked cells in 

 Uranotaenia doubts may be held, as though they are quite short 

 in many species, their length, according to Theobald's figures, 

 which form the only evidence before me, varies considerably, and 

 closely approaches in some species their length in such species of 

 Culex (s. latiss.) as have these cells rather shorter than usual. 

 In Culex they may be regarded as about i to | the length of the 

 wing, in Uranotaenia and Megarhinus, theoretically less than ^, 

 and even though in some species the}' may be less than \ of the 

 wing, the border line between the longer celled species and Culex is 

 very indefinite. 



' There seems no objection to this term, which is certainly lucid and con- 

 veniently brief. 



