NOTES ON BREEDING TEPHROSIA BISTORTATA, ETC. 125 



Notes on breeding Tephrosia bistortata and hybrid T. bistortatax 

 T. crepuscularia {ivith two plates). 



By E. A. COCKAYNE, F.E.S., F.L.S. 



As a supplement to the interesting hybridisation experiments 

 recorded by Mr. Tutt in the Transactions of the Entomoloijival Society of 

 London, 1898, the following notes may be of value. From a $ of 

 Tephrosia bistortata (crepuscidaria) obtained in Perthshire in April, 

 1P07, I bred a small number of imagines in March and April, 1908, 

 all of which had the deep chocolate lines and bold speckling typical 

 of this race. Two of the bistortata paired, and a S^ bistortata, a 

 specimen with white ground colour, and not much suffused or speckled, 

 paired with a small 2 ci-epuscidaria (biundularia), bred from Epping 

 Forest ova. The ova from both pairings proved fertile, and a 

 considerable number of the resulting larvae pupated. The pupro were 

 kept in an unheated room. 



The brood of pure T. bistortata emerged in two portions ; nine, all 

 2 s, appeared between July 25th and 29th, 1908, and twelve, six ^ 

 and six $ , between February 12th and March 23rd, 1909. The 

 insects of both parts of the brood were large, and differed but little in 

 colour and markings, none resembling the small white, feebly-marked, 

 second-brood English T. bistortata. 



The 3 s were much suffused with dark brown, though the colour 

 was not as dark as in the finest wild Perthshire specimens. 



The $ s had che dark markings paler and less rich than is usual, 

 and in some the ground colour was suffused with pale brown. All, but 

 especially the summer specimens, look rather dull and faded. 



The interest of this brood lies in the fact that T. bistortata is 

 normally single-brooded in Perthshire, and that when a second brood 

 is artificially produced, it resembles the first, and it is not totally 

 different as in the English second brood. 



The brood of hybrids also emerged in two portions, sixteen, all ? s, 

 between July 12th and September 25th, 1908, and ten, eight 3 s and 

 two ? s, between December 17th, 1908, and February 6th, 1909. The 

 summer and autumn specimens were all small and pale, closely 

 resembling the ? parent, while the winter and spring specimens were 

 larger and darker. Though one J is as dark as the $ parent, the)' 

 resemble T. crepuscularia more than T. bistortata. 



The wings look more pointed, and the elbowed line is more oblique, 

 with but little dark shading outside it ; the speckling is finer, and the 

 whole appearance neater than that of Perthshire T. bistortata. 



The 5 s, though small, are in colour and markings more like 

 T. crepuscularia than T. bistortata. Owing to the long, drawn-out 

 period of emergence, I was not able to attempt any further crossing 

 between the hybrids inter se, or between a hybrid and a T. bistortata. 

 Explanation of Plate XI. 



Tephrosia bistortata from Perthshire ova, two sections — (1) emerged July, 1908 ; 

 (2) emerged February-March, 1909. Third column captured specimens. 



Explanation of Plate XII, 



Parents of crossing of Tephrosia bistortata x Tephrosia crepuscidaria. Hybrid 



progeny of this crossing, two sections — (1) emerged July-September, 1908 ; 



(2) emerged December, 1908-February, 1909. 



