122 STUDIES IN AUSTRALIAN NEUROPTERA, V. 



primitive condition well. From this primitive state, two lines of 

 development may follow: — 



(1) Ciij^ may become fixed in its divergent position, and the 

 intercubital line may be developed in the usual manner between 

 the descending branches of Cui;, + M.. Various stages in this 

 process may be studied \vithin the genus Ghmoleon, while the com- 

 plete formation may be seen in Acanthaclisis and ^lyrmdeoii. 



(2) Cuib may become straightened out parallel toCuj, + Mo, the 

 intercubital line becoming developed between them, and parallel 

 to both. The beginning of this line of evolution is evident in 

 the forewing of Frotoplectron striatellum, Esb.-Pet., which is, 

 therefore, fairly primitive. In P. venustum Gerst., the forma- 

 tion is practically completed; w-hile in Creagris ^9/?*m6ews 01., 

 (Palsearctic) the development of the three parallel veins, with all 

 connecting structures reduced to simple series of cross-veins, 

 reaches the highest possible stage of evolution along this line. 



It would appear, therefore, that my estimate of the tribe 

 Creayrini, as the most primitive of the DendroleonthLce, is not 

 correct. They form, rather, a separate side-line of development 

 away from the main stem, culminating in a very highly specialised 

 genus, viz., Creayins. It should be noted, in this connection, 

 that the larva of Creagris is the only one amongst the Dendro- 

 leontince that is known to make pit-falls. It will now be of 

 special interest to find out whether the larvte of Protoplectron do 

 likewise. 



