110 



the Codling-moth (Carpocapsa pomonella, Linnseus) belongs; and is conse- 

 quently widely distinct from my Plum moth. Mr. Stainton further tells me 

 that, just as I anticipated in the Practical Entomologist, "in some years this 

 insect is injurious to the Plum-crop in England, but the moth is entomolog- 

 ically scarce, and few collections are well supplied with it." "I have not," he 

 adds, "obtained a single specimen for more than 20 years." 



"Sonasia prunirora is allied to /S'. janthinana, Duponchel — which, if I 

 remember rightly, has been bred from gall-like growths on hawthorn twigs, 

 though V. llernemaim, who gives no habitat for the larva, says that the 

 imago frequents sloe-bushes [the English wild plum] — but with the anterior 

 wings narrower, the pole mark frojn the middle of the inner margin more 

 obliquely placed, and with four distinct' transverse leaden-blue streaks from 

 the costa. In Janthinana there are no leaden-blue streaks. In the centre of 

 the pale dorsal [discal?] blotch is a distinct darker line, rather more de- 

 fined than in Janthinana. On the surface of the anterior wings are numer- 

 ous short longitudinal pale orange streaks, which give the insect a much 

 brighter appearance than we see in Janthinana. Lastly, the posterior wings 

 are, lowards the hind margin, blackish, and thei-efore much darker than in 

 Jantkifiana." 



The Larva, when 0.11 inch long, is about 6 times as long as wide, of 

 a dingy white color, with some fine short dusky hairs. Head, a horny 

 obsemieircular plate on the 1st segment behind the head, and a horny semi- 

 circular plate on the anal segment, all black and polished. Legs and pro- 

 legs, dingy white. When 0.18 inch long, the body is of a pale brownish 

 yellow color, and the two horny plates on the body are brown, not black, 

 but the head remains black. 



Described from one specimen found in a plum July 28th, and one (of 

 the larger size) found in Black-knot July 22d. The former was wounded; 

 the latter I isolated in a separate bottle, and subsequently bred the moth 

 from it. 



The cocoon spim by the larva is formed above ground, among the plums 

 from which the full-fed larva; have made their exit, or is sometimes attached 

 to neighboring substances. It is composed of dark-colored silk arranged 

 in the usual elongate-oval form. 



The Pupa I have not seen. 



Mr. V. Riley informs me, that according to H. N. Hum- 

 phreys, {Genera of British Moths,) the larva of a European species is 

 the same genus to which the Plurn IMoth belongs {Semasia wceher- 

 ana,) is supposed to feed on the inner tegument of the bark of plum- 

 trees, cherry-trees, apple-trees and occasionally laurels. This is only 

 another illustration of the law of "Phytophagic Unit}^," as I havo 

 called it, which has long been known to prevail to a considerable ex- 

 tent among the larvae of the Butterflies and the Moths, namely, that 

 the same group of Insects affects the same group of Plants.* I have 

 shown that this law also holds good among almost all the groups of 



*See Westwood Introd. II. pp. 321 — 2, etc., etc. 



