28 Records of the Indian Museum. [Vol. X, 



think all without exception are unanimous in the hypothetical 

 "' supernumary cross vein." 



Even Col. Alcock commits one serious error in describing the 

 venation. 



His wing of Tahanus is quite correct. In his wing of a mos- 

 quito, waiving the point that his 2nd marginal cell is more usually 

 termed the ist submarginal (since this is a matter that can be 

 regarded from two points of view), ha c )mmits a serious error in 

 not recognising the very obvious posterior cross vein, which he 

 terms his " anterior basal cross vein," stating that the posterior 

 cross vein is not present at all and that therefore there is no en- 

 closed anal cell. The presence or absence of the posterior cross 

 vein has no bearing whatever on the anal cell, which is always the 

 cell that lies behind the 5th longitudinal vein, or the lower branch 

 of it when this vein is forked, and it may be open or closed quite 

 independently of the posterior cross vein. 



Far be it from my desire, let it be understood, to in any way 

 condemn or undervalue Col. Alcock's valuible chapters on diptera, 

 than which I have seldom perused anything more concise and 

 clear, and it is refreshing to see that he eschews that, to me, parti- 

 cular bugbear, Theobald's " supernumary cross vein " and recog- 

 nises its true character, as the basal section of the 3rd longitudinal 

 vein. 



Anew and still more deplorable misconception than Theobald's 

 '' supernumary cross vein " is provided by Major Christophers in 

 a recent paper on the wing markings of the Ano heline group.' 

 This author postulates that " if the 2nd longitudinal vein 

 itself formed a direct junction with the ist, etc., etc.," continuing 

 '* some authors figure the vein as acting in this way, but I have 

 not found any example of an Anipheles wing shewing this arrange- 

 ment," though he admits it '' aopears to occur" in some other 

 Culicidae. 



This author therefore actually seriously suggests that the 2nd 

 longitudinal vein does not emerge from the ist either in a curve 

 or at a sharp angle (with or without an appendix at the flexure) 

 but that it is joined to the ist vein by a cross vein. The 2nd 

 longitudinal vein does most emphatically not " continue past this 

 cross vein," etc., to " lose itself in the wing membrane," but 

 both 2nd and 3rd veins emerge from the ist and 2nd respectively 

 in Culicidae, as they do in other f ami-lies. Is it not extraordinary 

 that present-day writers on mosquitoes find veins that giants of 

 dipterology like Wiedemann, Zetterstedt, L,oew, Schiner and the 

 late Osten Sacken and Verrall (two exceptionall}'- gifted exponents 

 of venation in diptera) all overlooked and that the 2nd and 3rd 

 longitudinal veins in Culicidae are suddenly found to have totally 

 different methods of origin to those in every other family of 

 diptera ? 



' Ann. Trop. Med. and Paras vii. No. i. 57, March 31, 1913. 



