COMMON WAVE. 267 



throughout its length or near the inner margin, and more rarely 

 the two are united ; in most of such aberrations the tips of the 

 fore wings are rather more rounded than in typical specimens, 

 and these are referable to ab, rotundaria^ Haworth (Round- 

 winged Wave). I have over a dozen examples of this form, all 

 of which were reared from caterpillars which had been kept on 

 short rations when nearly mature ; in some, the outer margin 

 of the fore wings is distinctly rounded, but in others it is much 

 the same as in the larger typical form, and one of these is shown 

 on Plate 107, Fig. 12. The ground colour occasionally assumes 

 a greyish tint, and sometimes this is tinged with pink ; more 

 rarely the general colour is leaden grey. 



The caterpillar, of which there are two broods, one in July 

 and another in September, feeds on birch, alder, sallow, etc. 

 It is purplish brown, spotted with white above, and greenish 

 below on the first three rings. There is also a green form with 

 purpHsh brown marks on the back. (Plate 105, Fig. 3, from a 

 coloured drawing by Mr. A. Sich.) The moth is out in May, 

 June, and August, and is generally common throughout the 

 greater part of the British Isles. 



Abroad, the range extends to East Siberia and Amurland. 



Common Wave {Cahera exanthemata). 



Somewhat similar to the last species, but sprinkled with 

 ochreous grey ; the fore wings have three greyish cross lines, 

 the first two less regular than those of pusaria, and the outer 

 one distinctly curved ; variation in the lines is pretty much the 

 same as in pusaria and its small form ab. rotimdarta. Of the 

 form showing the first and second lines more or less confluent, I 

 have seven examples reared from collected caterpillars ; six are 

 undersized, but the other is of quite ordinary size (ab. approxi- 

 mata, Haworth); another specimen, also bred, is thinly 



