oi 
corded from Northern or Southern Europe, nor from extra-European 
territory. 
The specimens I exhibit are—(1) The broods of 7: dzstortata, T. 
crepuscularia, and 7. ab. delamerensis, from which Dr. Riding selected 
the parents for his experiments. (2) Those used by Mr. Bacot for 
the same purpose. (3) The hybrids obtained by Dr. Riding. (4) 
The hybrids obtained by Mr. Bacot. A few remarks on each of these 
may now be useful. 
I. Parents used for Pairing in Dr. Ridine’s and Mr. Bacot’s 
fo) i coy 
Lixperiments. 
By a little judicious treatment in February and March, 1897, Dr. 
Riding obtained the emergence of 7? d7stortata, T: crepuscularia, and 
T. ab. delamerensis. ‘These insects were the broods from which the 
parents of the hybrids were selected, and were obtained by Dr. Riding 
as follows : 
(1) Z: btstortata.—These were (a) from eggs laid by a female of 
the second brood in July, 1896, captured at Clevedon (Somerset). 
(6) Eggs laid by female (second brood) bred by Mr. Bacot, also from 
Clevedon ova. The imagines emerged between February 17th and 
March 27th, 1897. A selection of these are exhibited. These are 
of the well-marked southern form, with suffused ochreous ground 
colour, distinct basal and subterminal bands, and strongly shaded on 
either side of the wavy antemarginal line = ab. adzefaria, Haw. 7 ¢ 
and to 2 ; the latter more strongly banded and less suffused than 
the males. 
(2) Z. crepuscularia.—These were reared from ova laid by a female 
from the York district, the ova having hatched June 3rd to 4th, 1896. 
The melanic form appeared with the type in almost equal proportions. 
The imagines emerged between March 7th and the end of the first 
week of April. These are of a rather more suffused form than those 
from our southern woods; this is probably due to the influence of 
the melanism that has produced ab. de/amerensis, a form that probably 
appears as a part of every brood in the York district, whence these 
were obtained. ‘The use of this rather suffused type-form has com- 
plicated the colour difficulties in dealing with the hybrids, but has 
made them more interesting. 8 gand to 9. 
(3) Z: ab. dedamerensis.—These were the imagines from pupz 
bred from ova laid by a 2 7. ab. delamerensis, captured in the 
York district. The eggs hatched May 3oth to 31st, 1896. Imagines 
of the typical form appeared with those of the melanic form from 
this batch of eggs; there were no real intermediates between the two 
forms ; emergence took place between February 26th and April 27th 
(few came out before March gth, and some as late as April 27th). 
Blackish grey in colour, deeply suffused, but with irregular grey 
patches, the white antemarginal line not particularly strongly marked. 
(4) Besides the above I also exhibit for Dr. Riding a series of 
T. bistortata (second brood). These are the progeny of specimens 
