LÉPIDOPTÉROLOGIE COMPAREE 443 



The females of sonaria, after pairing with lapponaria, lay 

 their eggs very freely and practically ninety per cent of them 

 prove fertile. The little larvae as they emerged, were placed, 

 some on yarrow {Achillea Millefolwm) and some on birch 

 {Betula alba) and hawthorn {Cratœgus). They took very readily 

 to the last two food plants but failed to touch yarrow. Later 

 in life, after they had fed on hawthorn for some time, I tested 

 them with Erica tetralix (the usual food of Scotch lapponarïà) 

 but they refused to eat it. although they look readily to sallow 

 {Salix câpre a). 



Description of larva. 



The young larva was very like that of lapponaria but no 

 attempt was made to make a detailed account until the last instar 

 was reached. 



Length of larva 3,4 cm. 



Head 2,6 mm. 



Greatest breadth 4 mm. 



The larva, in shape, is decidedly shorter and stouter than that 

 of lapponaria. 



Head. The head is much smaller than that of zonaria; 

 although not so small as in Lapponaria. The epicranial lobes 

 too, are fuller, but the most important différence is the much 

 greater size of the frons, which in lapponaria is very small. The 

 colour of the head is purple of a paler type than in lapponaria, 

 and the black spots are more dot like but fewer in number. The 

 mouth parts are quite black and lack the paler edging seen in 

 ail the other hybrids. 



Body. The ground colour is pale purple but is sometimes 

 quite whitish or greyish. It is mixed, hère and there, with large 

 numbers of minute black spots. The longitudinal stripes are 

 fairly well developed and, whilst those on the mediodorsal area 



