120 



STUDIES IN AUSTRALIAN NEUROPTERA, V., 



continues the line of the stronger upper trachea beyond the point 

 where the partially aborted lower trachea ceases to exist, and 

 must, therefore, be regarded as a composite vein, whose double 

 origin is now only indicated by the oblique vein placed above it. 

 Thus, in the case under consideration, we have two composite 

 veins formed, viz., the aubito-median, Cuj^ + M.,, (whose structure 

 I worked out in No.l of this series of Studies), and the cnbito-anal, 



1 A + Cug, whose existence 

 has not been before sus- 

 pected. The oblique vein 

 indicating the presence of 

 the former is Om, that in- 

 dicating the presence of 

 the latter is Oc. The com- 

 plete, correct, amended 

 notation for the forewing 

 of Xantholeon helmsi Till- 

 yard, is given in Text-fig. 

 2. In Text-fig. 3, I oflPer 

 a phylogenetic series of 

 stages to show the evolu- 

 tion of the Myrmeleontid 

 type from the original archaic formation of these veins, as still 

 preserved for us in the archaic Hemfirohiidce^ Drepanepteryx, and 

 Drepanacra. 



* Phylogenetic series illustrating the evolution of the cubitus in the 

 wings of Hemerobiidoi and Myrine.Ieontiche. — Series a, h, c, three stages 

 leading to the reduced Hemerobiid type, also to the type found in hmd- 

 n-inr/s of Xymphidce and MyrmeJeontidoe. With a, compare forewing of 

 Drepanepteryx', with b, compare hindwing of Drepanepteryx; with c, com- 

 pare wings of Drepanomina. The final stage, in which the furrow / is 

 completely eliminated, is not shown in this figure. — Series a, b, d, three 

 stages leading to the formation of the cubito-anal vein in the forewing of 

 the Myrmdeontidn', by fusion of the veins lA and Cuo. In c?, the basal 

 part of Cuo is indicated by the cubital oblique vein Oc. 



Lettering as on p. 118, and, in addition, k, the point destined to become 

 ciif, and s, the sector of Cu^ destined to become Cuib. 



Cuib 



Text-fig. 3.* 



