BY R. J. TILLYARD. 



285 



(3). The presence of at least one false or secondary origin for the 

 radial sector in the hindwiiiy (Text-fig. 2). At least one false 

 origin (a?) is present in all Hemerobiidce known to me, as well as 

 in all Chrysopidce. Owing to the true origin of Rs being placed 

 too close to the base of the wing to afford the necessary support 

 to the vein, the cross-vein placed next distad from it, between 

 R and Rs, becomes strengthened and oblique, while the portion 

 of Rs lying basad to it becomes weakened and often bent, and, 

 in many cases, fuses basallv with M. The result can be seen 



Text-f5ff.3. — Venation of Hemerohius humnli Linn. 



very clearly in Text-fig.4. The false origin a; (originally a simple 

 cross-vein) appears to be the real origin of Rs, while tlie small 

 portion of Rs, lying just basad to x, takes on the form of a cross- 

 vein. In Drepanepteryx (Plate xiii.), a second cross-vein follows 

 suit, and we have two false origins, x and x!. In Megalomina 

 (Text-fig. 8), we see an intermediate condition, the second cross- 

 vein being only partly specialised, though the first has become 

 greatly lengthened. In Hemerohius (Text-fig.3), two false 

 origins are present, but are very short, owing to the close 

 approximation of Rs to R basallv. 



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