•230 Ilyhiifh of Bistonine Moths 



The piiiiiaiy liybrids reared up to the present are as follows: 



Lycia hirtaria ^ x Ithysia zonaria % (PI. XVII) = Lycia hybr. denliami. 

 Lycia hirtaria ^ x Ithysia go-aecaria % = L. Iiyhr. buluveci. 



Lycia hirtaria (^ x Poecilopsis jwrnonariu J — L. liyhr. pilzii. 

 Ithysia zonaria. ^ x Lycia hirtaria % (P1.XVII)= X. /(j/tr. harrisoni. 

 Ithysia zonaria ^ x Poecilopsis lapponaria ? = /. hybr. nierana. 

 Ithysia zonaria ^ x Poecilopsis pomonaria ^ = I. hybr. lanc/ei. 

 Poecilopsis pomonaria ^ x Lycia hirtaria J = P. hybr. hunii. 

 Poecilopsis ponionaria J" x Ithysia zunaria. % = P. hybr. helenae. 

 Poecilopsis lapponaria ^ x Ithysia zonaria % = P. hybr. sniallmani. 



Similarly, the secondary hybrids are appended : 



Poecilopsis ponionaria ^ y. L. hybr. pilzii % = P. Iiybr. brouksi. 

 Lycia hybr. pilzii ^ x L. Irirtaria $ = L. hybr. burrowsi. 



P. hybr. hunii ^ x L. Iiirtaria % = P. hybr. hnlli. 



Up to the present, only one tertiary hybrid, that is to say a hybrid 

 with one of my secondary hybrids as a parent, has been obtained. This 

 form has been successfully reared to the pupal state and I trust to have 

 the pleasure of seeing the imagines next spring. Its parentage is 

 L. hybr. burrowsi ^ x L. hirtaria % and I am calling it L. hybr. adkini 

 in honour of my friend Mr. R. Adkin, who has assisted me in many ways 

 during the course of my many experiments. 



I have no intention of giving a prolonged account of the comments 

 I made in my work in Lepidopteroloyie comparee upon the various 

 phenomena observed which demanded special treatment. Two of these 

 features, however (in my eyes at least), are so important that I have 

 reserved them for a special pajjer to be published shortly. 



The various points are given below and a brief resume of the 

 discussion in my longer paper is added to each. 



(1) The great constitutional strength of the larvae. 



(2) The growing sterility of the printary hybrids as the specific 

 divergence between the parents increases. 



I pointed out that " strength " in the case of all of the crosses 

 behaved as a Mendelian dominant, and that, granting the jjossibility of 

 aberrations (mutations) po.ssessing great constitutional strength, these 

 two factors alone would result, in some cases, in what could only be 

 classed as new species. 



