Hybridising T. bistortata and T. crepuscularia 25 
RECIPROCAL CROSSINGS OBTAINED.—Fertile reciprocal 
crossings obtained were :— 
1.—T. bistortata f x T. ab. delamerensis 2 .—Paired 
March 9th. 
2.—T. ab. delamerensis $ x T. bistortata 2 —Three 
pairings. a. Paired February 26th; ova deposited 
April 6th. @. Paired March 5th. y. Paired March 9th ; 
ova deposited April 7th. 
3.—T. bistortata f x T. crepuscularia 9 .—Two pair- 
ings. a. Paired March 9th; hatched April 8th—9th. 
8. Paired March 9th; hatched April 8th—9th. 
4.—T. crepuscularia ¢ x T.bistortata 9° .—Paired Feb 
ruary 27th. 
Crossings that failed were: (1) 7. crepuscularia f x 
T. bistortata 2. Paired February 27th. (2) 7. ab. dela- 
merensis f x T. bistortata @. Paired March 4th. 
Hysrips.—I. Hybrids between 2 T. bistortata x 2 T. 
ab. delamerensis. [Ova received from Dr. Riding.]—They 
are part of Dr. Riding’s cross marked I, eggs laid March 
15th, hatched April 26th-27th. Examined 21 specimens 
=11 males, 10 females. 
Af 49 The males dead grey, not ochreous, fairly 
well marked, showing the more definite 
markings of 7. bistortata; the females are 
_ almost pure white with the fuscous lines dis- 
| tinct, but the transverse shading usually 
united with them almost obsolete. 
FG Ge. These may be classed as ab. delamerensis 
although six males only carry the dark ground- 
colour of this form ; one of the males, and two 
of the females uniform dull grey (-black), 
weakly developed, almost without markings, 
and with a tendency to be diaphanous ; the 
remaining four females, saved for eggs, are 
worn, but were evidently of the same type. 
[This ill-developed form of ab. delamerensis is 
undoubtedly due to the crossing, the rapid 
feeding of the larva, and the production of a 
second brood, a phenomenon never occurring 
in nature. The other portion of this brood 
shows the same peculiarities in a rather less 
marked degree. | 
~I 
oY 
ie ade 
