Small ILrmme Moth. 



435 



Anterior wings ordinarily of a leaden white, with about thirty 

 remote minute black spots, disposed somewhat regularly in lon- 

 gitudinal rows, but on the hinder margin they are more irre- 

 gular, and tend to a transverse disposition : cilia livid. Pos- 

 terior wings lead-coloured : cilia rather paler. Extremely 

 variable : some examples having the ground of the anterior wings 

 white; others with the costa livid, and the inner margin white; 

 some with a livid or pale lead-coloured central cloud; others, 

 again, entirely of a pale or deep lead colour ; and all interme- 

 diate shades occur : the number of spots also varies. {Stephens 

 Illust. Brit. Enf. Lepid.^ vol. iv. p. 243.) 



The caterpillar {fig. 117.,^, rather magnified) of this moth 

 is of an ashy white colour, with a bi'ownish head, and a 

 number of small black spots, of which the largest form a series 

 on each side of the body. It has sixteen feet, the three 

 anterior pairs being articulated, and attached to the three an- 

 terior segments. The four following pairs are membranaceous, 

 false, ventral legs ; and the terminal pair anal, and also mem- 

 branaceous. They are below the middle size, and the body 

 is smooth. In regard to the predilection of this caterpillar for 

 any particular kind of food, I have already noticed that only 

 some kinds of apples were affected ; which is the more remark- 

 able, because its principal food (whence its specific name is de- 

 rived) is the bird cherry, although the white thorn is also even 

 more subject to its attacks ; whole hedges being sometimes en- 

 tirely defoliated in summer, and covered with webs, The re- 

 mark of De Geer and Reaumur {Memoires, torn ii. mem. viii. 

 p. 324.), that caterpillars, in general, prefer that particular kind of 

 plant upon which they were produced, will enable us in some 

 measure to account for this predilection ; but, unless we suppose 

 that the parent moth always chooses, in like manner, the kind of 

 tree upon which it had fed whilst in the caterpillar state for the 

 reception of its eggs, we can hardly account for the fact, that in 

 one situation the white thorn alone is attacked, and the fruit 

 trees untouched ; whilst in another it is only one kind of apple 

 tree that is injured. 



It is a peculiarity in the history of this insect, that it is not 

 only social in the caterpillar state [Jog. 118. a), but that it retains 

 its sociality during the period of its pupation (6), the cocoons 



FF 2 



