May iSg;.] 



PSyCHE. 



239 



remain peniianently. Fig. 7 tr., rep- 

 resents tliese secondarv veins in the 





edge of the lore wing of Laverna vi<in- 

 cUa, arising from a main trachea (/r) 

 p a s s i 11 g 

 throng h 

 vein I, two 

 of t li e 

 twigs ex- 

 tending to 

 tlie cen- 

 tre, show- 

 ing that 

 the hitter 

 has no 

 homology 

 with a 



vein. Onlv rarely and in 

 strongly developed thick 

 folds are the cross-tracheae 

 provided with a chitinons 

 thickening, as for exam- 

 ple in Cossus ligtiiperda. 

 .Since from such accessorv 

 traclieae the cross-veins in 

 lepitiopterous wings are de- 

 veloped, we can recognize 

 in them the homologies of 

 the net-veins in reticulated 



venations. There is no sharply defined 

 difierence between reticulated and a 

 non-reticulated venation ; no genetic 

 dirterence exists between the two 

 kinds of venation, since there occur 

 true Blattidae with and without a 

 reticulated venation (Spider). 



It may be remarked that Spuler 

 agrees with Brauer and Redten- 

 bacher, as well as Haase, that 

 Adolph's system of con\ex and con- 

 cave veins is entirely erroneous. 



We adopt, then. .Spuler's system of 

 venation, and earnestly trust that it 



Fig. s. 



