Lasiocampa. 35 



I2th) ; 3 {meridional is x viburni, from brown - haired larva) x % viburni 

 (August 12th) ; 3 sicula x ? ?neridionalis (August 24th) ; 3 sicula x ? 

 {meridional is x viburni, from brown- haired larva) (August 20th). In 1898 a 

 cross of 3 [{meridionalis x viburni, white-haired) X {meridional is x viburni, 

 white-haired)] x ? sicula, was obtained. 



Bacot notes that there was perfect fertility between all the forms 

 with which he experimented, his losses occurring chiefly in the larval 

 stage, and being possibly largely due to overcrowding. Warburg's 

 experience suggests that the brown-haired larvae of L. meridional is 

 X vibui ?ii produce a very small proportion of ? s, the white - haired 

 larvae of this cross more than the normal proportion. 



We have carefully examined the specimens bred by Warburg 

 and Bacot. To us the most interesting of the crossed imagines 

 appear to be the following : 



1. L. hybr. bacoti* {pzmeridionalis x viburni). — a. The 3 s (30) are scarcely 

 distinguishable from the male parents (the progeny is from four pairings) ; the 

 females are distinctly yellower than the ? parents, which are more than usually 

 red even for viburni (Warburg coll.). fi. 5 3 s, all showing rather more than a 

 tendency to the widening of the transverse bands of fore- and hindwings ; two 

 have them somewhat wider even than any viburni examined, and in this respect 

 approach British quercus (Bacot coll.). 



2. L. hybr. ivarburgi {—quercus x meridionalis). — a. 3 3 s and 4 ? s, the 

 former quite of the broad-banded English quercus type ; the ? s also show this broad- 

 ening of the transverse bands (Bacot coll.). The larvae also showed the predominant 

 characteristics of the English quercus strain (Bacot). [3. 4 3 s and 8 ? s, the 

 offspring distinctly like British L. qicercus in both sexes, the 3 s with the 

 characteristic tendency to wider bands ; the ? s less red and more yellow than 

 the ? parent (Warburg coll.). y. 1 1 3 s, no ?s; the offspring small; the 

 outer marginal area weak in colour compared with the 3 parent ; the transverse 

 bands narrow (Warburg coll.). 



3. L. hybr. intermedia (=zsicula X meridionalis). — a. 3 3 s, I ?. The 

 ground colour rather nearer the darker tint of meridionalis than the more russet 

 hue of sicula ; the transverse band of forewing definite and narrow ; the hindwing 

 with the orange marginal area of sicula altered to the brown marginal area and 

 narrow yellow transverse band of meridionalis ; the ? retains the russet tint of 

 sicula, but has not the distinct pale outer marginal area of that form (Bacot 

 coll.). /3. 2 3 s and I ? emerged the first year, the males of russet hue of sicula, 

 but the hind marginal area of hindwing surrounded with brown as in meridionalis ; 

 2 3 s and 2 ? s of same batch emerged second year, one weakly pigmented 3 

 of above form, the other 3 with full yellow marginal area to hindwings as in 

 sicula; ? s small, and had evidently been ill-nurtured (Warburg coll.). 



4. L. hybr. prouti {=zsicula x quercus (Paris)). — a. 8 3 s and 10 ?s; the 3 s 

 almost identical with sicula except for a gradual fading of transverse band of 

 forewings into the marginal area, and a slight trace of a marginal brown shade 

 edging the orange marginal area of hindwings ; the ? s distinctly of the ? 

 parent form, yellow, and quite unlike the warmer tinted ? sicula (Warburg 

 coll.). f3. 21 3 s and 7 ? s. All the specimens comprising this brood larger, 

 otherwise the 3 s very like the last in ground colour, and follow the 3 parent ; the 

 outer margin of hindwing rather less orange-yellow and more shaded with brown 

 externally, and hence nearer quercus. The ? s also yellow, nearer quercus than 

 sicula, although there is a distinct trace of the warmer sicula hue than in ? s 

 of preceding brood. 3 ? s (of same brood), emerging after second year in pupa, 

 are very dark reddish-ochreous, the outer marginal areas of hindwings scarcely 

 differing in tint from the rest of wings (Warburg coll.). 



5. L. hybr. complexa [znsicula x {meridionalis x viburni, brown-haired larva)]. 

 — 8 3 s and 2 ? s ; the males have distinctly wider transverse bands to forewings than 

 sicula, the ground colour showing trace of the sicula tint, but on the whole both 

 bands and colour are nearer those of meridionalis x viburni than of sicula ; the hind- 

 wings in all the specimens with distinct brown marginal border, in three quite as well 

 defined as in viburni ; the ? s follow the ? parent {meridionalis x viburni). 



* In the imaginal stage, the cross bacoti is practically indistinguishable from 

 the parent forms viburni and nieridionalis. The interest in this cross and in the 

 parent forms lies in the characters presented by the larvse. 



