Insects. 3959 



Nut. Two species, a large and a small larva ; the perfect insects 

 are parallel to, if not identical with, the two species from the 

 hornbeam. 



Oak. Two species of larvae were distinguished, a pale-coloured and 

 a dark-coloured one. It would, however, appear that there are 

 two species of the latter, as from them have been bred both N. 

 ruficapitella and atricapitella, which can no longer be considered 

 as sexes, since several pairs of the latter were taken in copula 

 last summer. The pale larva produced N. subbimaculella. 



Rose. From the mode of mining, and the colour of the cocoons, 

 there is little doubt that two species feed on the rose : — one, 

 which had always been confounded with ruficapitella (see Lewis, 

 in Ent. Mag. i. 422), but of which one sex has the tuft of the 

 head black, was observed by De Geer, and Goeze has given to 

 his insect the name of anomalella ; the other species, which I 

 have not yet bred, may probably be the continental centifoliella. 



Sallow. Only one species of larva has been observed, the perfect 

 insect from which belongs to the Floslactella group. 



Sloe. From the rather common blotch-miner of the sloe, I have 

 bred a species of the Ignobilella group. I have a single leaf 

 mined in a different way, but have not yet bred the moth from it. 



10. If the Species are so numerous, and so very closely allied, how 

 are they to be distinguished ? This, no doubt, is a difficulty, and if 

 we collected only the perfect insects, it would be one not easily an- 

 swered ; but by collecting and observing the larvae, we ascertain be- 

 forehand the distinctness of a species, even if the imago should afford 

 us no character. 



If you wish to separate Acronycta Psi from tridens, you must breed 

 them both ; so it is with the Nepticulae. 



The points to be borne in mind with a view of distinguishing the 

 species, are: — 1. The food-plant. 2. The mine. 3. The larva. 4. 

 The cocoon. 5. The perfect insect. 



1. The Food-plant. However much we may ultimately find it 

 necessary to qualify the assertion, it is no doubt advisable to 

 assume that no species feeds on two different kinds of plants. 

 The bramble, strawberry, and Geum are allied plants, and may 

 all be fed upon by N. aurella ; but to assume that because they 

 are allied plants, the miners in them are without doubt aurella, 

 would be jumping to a conclusion, and probably retard the dis- 

 covery of species. The apparent identity of the two species 



