Alexander — Crane Flies 225 



Radius (K) is lypiccilly fivc-hraiiched. Tlie principal l)i-aiioh (R^) runs 

 parallel In the anterior margin, at about mid-length giving otif a strong branch, 

 the radial sector (Us) or praefnrca, which, in turn, is dichotomonsly twice forked. 

 In most Tipulidae, the two j)()stei'ior branches, R^ and R'"', are fused into a single 

 branch, R*^^ 



Media (M) occupies the median area of the wing. Its behaviour is like that 

 of the radial sector, being dichotomonsly twice forked. The upper fork carries 

 the branches M^ and M-, the lower fork carries the branches M^ and M*. In the 

 system used, M^ and M^ are iiiterpreted as being fused, M^+*, or, for convenience, 

 M^ alone in the Limnobiinae. 



Cubitus (Cu) is a powerful vein lying between media and the first anal vein; 

 it is forked once, the anterior branch (CUi^) being united with the posterior' branch 

 of media either bj' direct fusion or by the short medial-cubital (m-cu) crossvein. 



Behind cubitus are one or two simple veins, the anal veins (A). 



There are five primary cross-veins, which are indicated by small letters : the 

 humeral (h), in the base of cell C; radial (r), in cell R^, connecting R^ with 

 either R-+3 or R^ alone; radial-median (r-m), connecting the posterior branch 

 of i-adius Avith the anterior branch of media; medial (m), connecting the upper 

 foi'k of media Avith the posterior fork, and, if present, closing the discal cell 

 (first M-) ; medial-cubital (m-cu) is present only in the generalized forms, being 

 obliterated by the fusion of the anterior branch of Cu on the anterior branch or 

 ivnnk of M. 



The cells of the wing take their name from the veins immediately before or 

 iji front of them, as indicated by the accompanying figures. In the case of fused 

 A'cins, the cell takes its name from the last element of the fusion. 



Recently Dr. Tillyard (-) proposed an important modification of the 

 Conistock-Needhani system. This modification involves the medial and cubital 

 fields, the principal features being shown on fig. 336. According to this interpre- 

 tation, which, in the writer's opinion, is very probably the correct one, media 

 isjsonsidered as having four persistent branches, M^ and M* being separate; the 

 latter branch corresponding to the l)ranch Cu^ of the Comstock-Needham system. 

 Cubitus is interpreted by Tillyard as having Init a single primary branch, C^ 

 corresponding to Cu^ of the Comstock-Needham system. In the Panorpoid 

 Complex, Tillyard holds that cubitus forks close to the wing-base, the posterior 

 branch, Cu- being semiatrophied and lying close behind the primary branch of 

 cubitus. 



(2) Tillyard, R. J. Tlie Panorpoid Complex. Part 3: The Wing-Veiiatiou. Proe. Liiui. 

 Soc. N.S. Wales, xliv, 1919, p. 533-718. 



