34 BRITISH LEPIDOPTERA. 



wanting in the others. In some cases the effect of temperature is so 

 considerable, that some of the forced L. var. callunae would, as regards 

 colouring, in the absence of data, pass for L. quercus, whilst the L. quercus 

 that was 7 1 days in pupa at the lower temperature, is very dark for the 

 typical form. 



The experiments made by Bacot and Warburg in crossing various 

 races of L. querctis, have proved exceedingly interesting. The races 

 that have been used for the purpose of these experiments are as 

 follows : 



1. L. var. sicula, Staud., the most specialised race of this species ; J s with a 

 russet- rather than chestnut -brown ground colour, a very narrow, straight, transverse 

 band to forewings, and a wide orange-yellow hind marginal area extending from the 

 band to the fringe of the hiudwings ; $ s a little smaller, somewhat darker, other- 

 wise very like our British ochreous forms, all the wings uniformly tinged with 

 reddish, the marginal area of the hindwings pale unicolorous. 



2. Z. var. meridionalis, Tutt, usually known as the south of France form of 

 quercus. This is the most extreme form, in which the <? shave very narrow transverse 

 yellow bands on fore- and hindwings, and dark ground colour ; ? s yellow, with 

 scarcely a trace of reddish in ground colour, the forewings duller than hindwings. 



3. L. var. vibumi, Gn., $ s scarcely distinguishable from var. meridionalis, the 

 transverse bands slightly wider on both fore- and hindwings ; ? s generally exhibiting 

 a reddish tint in ground colour. [The great difference between var. meridionalis and 

 var. vibumi occurs in larval stage.] 



4. L. quercus (ab. latovirgata) , <$ s with rather wider transverse bands, 

 the ground colour somewhat redder ; ? s vary considerably from yellow- to reddish- 

 ochreous. 



5. Z. var. callunae, Palm., <? s with very dark ground colour, with well-marked, 

 but not specially broad, transverse band, often with a yellow patch at base of fore- 

 wings ; the transverse band of hindwings rather distant from margin, and turning 

 down rather sharply at anal angle ; ? s much darker than in other forms. 



The parents from which crossings were obtained were as follows : 



1. Z. var. meridionalis (mixed families). 2. Z. var. meridionalis (a single 

 family). 3. Z. var. vibumi (a single family). 4. Z. var. vibumi (from collected 

 larvae). 5. Z. quercus, from Dorsetshire. 6. Z. hybr. meridionalis x vibumi, from 

 white-haired larva?. 7. Z. hybr. meridionalis x vibumi, from brown-haired larva?. 

 8. Z. var. callunae, from Aberdeen. 9. Z. var. sicula, from Sicily. Mr. 

 Warburg had also crossed ?neridionalis x callunae and obtained ova. 



The actual crossings obtained by Bacot in 1897 were 23 in 

 number, of which, however, 6 were duplicate. Of the remaining 17, 

 4 were pairings between moths of the same races, 13 being crosses 

 between different races. These were as follows : 



J meridionalis x ? vibumi (July 1st) ; J vibumi x ? quercus (July 

 loth); <$ (meridio?ta/is x vibumi, from white-haired larva*) X ? quercus 

 (July 1 oth) ; $ x ? meridionalis (July 18th) ; $ (meridionalis X vibumi, from 

 brown-haired larva) x $ meridionalis (July 19th); $ vibumi X ? callunae (July 

 19th); $ (meridionalis x viburni, from white-haired larva) x ? vibumi (July 

 19th); cT (meridionalis x viburni, white-haired) x ? meridionalis (July 19th); 

 d (meridionalis x vibumi, brown-haired) x ? vibumi (July 25th) ; s x ? 

 (meridionalis x viburni, white-haired) (July 28th) ; j querctis x '? meridionalis 

 (July 28th) ; d" X ? viburni (July 3 1st") ; S (meridionalis x vibumi, from 

 brown-haired larva) x ? (meridionalis X vibumi, from white-haired larval 

 (August 3rd) ; j 1 x ? (meridionalis x viburni, from white-haired 

 larva) (August 3rd) ; <? (meridionalis x viburni, from brown-haired larva) 

 X % meridionalis (August 71I1) ; $ x ? (meridionalis x viburni, both 

 from brown-haired larvae) (August 9th) ; <r meridionalis x ? vibumi (August 



I he larvae oi the first crosses between viburni and meridionalis, in all easts 

 divided into two scries, following the larval forms o[' the parent, VIZ., one series 

 white-haired, the other brown-haired. When progeny resulting from this cross have 

 been used, the particular larval form from which the insect came is indicated. 



