THE! Vol'NCi NATURALIST. 



95 



Larva — Black with ochreous branching 

 spines, with black tips. The body is much 

 speckled with pale or white warts. Riving it 

 a grey appearance. 



Pupa.— Similar in general appearance to 

 others of the genus, but the points at the 

 head arc more distinct than usual, being 

 widely separated, and well pointed. 



Food Plants -Kim appears to be the 

 favourite food in this country, but many 

 others are eaten occasionally— Cherry and 

 Tear, several species of S'tli.v, Aspen. Wvch 

 Elm and White Beam Tree. Newman says 

 that Cherry is the tree generally preferred in 

 France. 



Times of Appearance — The imago 



emerges in July, but retires early for hyberna- 

 tion. They pair in April or May, and the 

 Kgs are laid in large batches on the twigs of 

 the selected plant. The larva is full fed by 

 the end of June or July. It does not remain 

 [more than two or three weeks in pupa. 



Habitat - -This is a Butterfly that fre- 

 jquents the borders or outskirts of large w oods, 

 lor lanes well-bordered with trees suitable for 

 (the larwe. It sometimes comes to sweets. 

 In Kngland it is most plentiful in the South- 

 ern Counties, occurring less abundantly in 

 Ithe Midlands, and become quite rare in the 

 [Northern Counties where it is only an occa- 

 sional visitor. It is not recorded from 

 ■Scotland nor Ireland. On the Continent it 

 lis widely spread only being wanting in the 

 [Polar regions, it is also found over the greater 

 ■part of Asia. In the Kntomologist for 1874, 

 [Page So, will be found a record of its occur- 

 rence in Newfoundland on 26 Deer. 1872. 

 Kvirby gives no American locality, but J -album, 

 IBoisd. a variety of V- album W-V. is found in 

 the I'm ted States. We don't know" this 

 Variety, but F-album, is very close to Poly- 

 chloros and possibly Mr. KeHv.s. who made 

 the above record, confounded the two, but if 

 borrect, it is the only one we know of, of its 

 occurrence on the American continent. 



Variation.— Not a variable species in 

 Kngland, and we never saw the slightest de- 



■ parture from the type. A form with confluent 

 • spots is called Testudq, Ksper, another is called 

 P\;omc!a, Pre. They are both abnormal 

 forms, not deserving distinctive names. 



Allied Species— We have already 

 spoken of V. album, as being closely allied to 

 Polychloros. It is richer in color, has a white 

 spot on the eosta of the hind wing, where the 

 other is yellow, and a distinct white spot 

 i between the outer costal spot, and the black 

 marginal band. The blue lunules of the 

 hind wing are entirely wanting, but there is 

 a row of lighter spots within the black of the 

 1 inner border. Close as this species is. there 

 ' is another ( Xanthomclas, KspJ still closer. 



Xanthomclas is redder than Polychloros, but not 

 1 so rich in hue as V -album . The blue lunules 

 , on the hind v. Lag, that are wanting in the 

 latter, are larger in Xanthomelas than Poly- 

 chorus. On the costa oi the hind wing, the 

 portion between the black spot and the dark 

 margin, that is white in V-albunt, and yellow 

 in Polychloros is only noticeable in Xanthome- 

 las as a slightly paler shade. On the fore 

 wing the outer costal spot conies very close 

 to the black of the border, and there is a 

 distinct white streak between them. In Poly- 

 choros this is a yellowish, in V -album a 

 white spot. These are three exceedingly 

 interesting species, and though the larvae are 

 said to differ considerably, they are all w illow- 

 feeders. One peculiarity of the three insects 

 is, that each have one or more of the mark- 

 ings in excess of both the others. Thus 

 Polychloros has most yellow, Xanthomclas most 

 blue, and V -album most white. Supposing 

 one to have sprung from the other, or the 

 three from a common ancestor, it is difficult 

 to say how the divergences have taken place. 



Parasites- — Ichneumon iKCiatorius. and 

 cessator have both been reared from this 

 species on the continent as we learn from the 

 Kntomologist for December last. We are 

 not aware that any parasite has been obtained 

 from it in this country, but as both these 

 species are British, it is certain that observers 

 only are wanted to find them here. 



