No. 642] SHORTER ARTICLES AND DISCUSSION 191 



4 (Fig. 1, d,e). In two further cases, this type of lateral marking 

 was continued in the form of less distinct marginal blotches on 

 valve 3. The marginal blotches on valve 4 may accompany an 

 otherwise ''normal" pigment pattern (10 examples in 219 ex- 

 amined; Fig. 1, d), or may be present where there is evidence 

 of a tendency for the formation of a distinct axial stripe (five ex- 

 amples; Fig, 1, e). 



It is evident, then, that in Chitons color pattern variations 

 may occur in such a way as to affect single valves only (and, in 

 Chatopleura, specifically valve 2 or 4) ; and either quite inde- 

 pendently of this type of variation or accompanying it, may also 

 aft'ect all valves in the series simultaneously. Such variations are 

 quite independent of age. 



"W. J. Crozier 



FUGITIVE NET-VEINING IN THE CICADA 

 (IIEMIPTERA) 



TiLLYARD has lately noted ^ that, besides the chitinized veins 

 whicli serve for the support of the insect wing, there exist in 

 some eases at least fugitive blood-veins during the expansion of 

 the wing, which later collapse and more or less completely dis- 

 ap])ear when tlio wing dries. In the Lepidoptera 1st A and the 

 base of M are veins of the same character, and possess trachese 

 like otliei- loMLntu.linal veins in that order. In every particular 

 except \\w <ilts(Mi( f ehitinization these appear to be true veins. 



