Hybridising T. bistortata and T. crepuscularia 27 
most ochreous. Comparison with Dr. Riding’s parallel 
(IT) cross, many of which were much longer in the pupal 
stage, 1s instructive. 
Ill. Hybrids between f T.bistortata x 9 T. crepuscularia. 
—Of this cross there were two different broods. Of the first 
(a), marked 3a in Bacot’s pairings, the larvee for the most 
part followed the % parent (bistortata), only a few have the 
apex of the A. mark open asin the 2 parent; full-fed from 
about May 16th—20th. 22 specimens examined—l4 ¢ 
and 8 2. These emerged in June with the exception of 
two which came out in July. 
14f¢ 82 These are an exceedingly uniform batch, 
the superficial resemblance to second brood 
T. bistortata being very marked. The sexual 
dimorphism marked; the females whiter, 
clearer, and less mottled than the males. 
There is a distinct absence of ochreous and a 
tendency to the suffusion noticeable in pure- 
bred Yorks. 7. crepuscularia. [None of these 
emerged late, and none shows any tendency to 
become dark. ] 
14f 89 
B. (2 T. bistortata x 2. T. crepuscularia.)—Of the other 
brood of this cross (marked 38), a fair number of the larvee 
fed up and pupated very quickly, but others fed up slowly 
and did not go down until the earliest specimens had 
commenced to emerge; larve unhealthy, a large proportion 
died. I examined 9 specimens—6 males and 3 females. 
Four minute specimens—i3"(f), 18°22), 14°01). 
These small specimens emerged in late June, two normal 
specimens in early July, one on September 29th, and two 
late in October. 
ig 3 These are pale and practically without 
markings, although faint traces of the various 
lines can be seen in 1 f and 19; the second 
small 2 with hindwings crippled ; these three 
specimens measure only +3” in expanse. The 
other is also a pigmy, but fuller winged 
and better marked, being 1” in expanse. 
