ARBORETUM AND PRUTICETUM. 



PART III. 



The larvae of Saturnia Pavonia minor feed on various species of osier. 

 Lozotae v nia cruciana, a small but beautiful tortrix, lives on a dwarf mountain 

 Salix. Liparis (Leucoma Steph.) salicis is, in many years, very abundant on 

 different willows. Several species of the very showy genus of JVbctuidae, Ca- 

 tocala, also feed, in the larva state, upon several species of Salix. These 

 caterpillars exhibit a very interesting instance of deceptive similarity to the 

 plants on which they feed; their colours being of a pale greyish brown, dot- 

 ted with black, and the sides of their bodies being furnished with a membrana- 

 ceous lobe, fringed with short whitish hairs, which are applied close to the sur- 

 face of the twigs, so that it is very difficult for an unpractised eye to perceive 

 them, or to distinguish them from bundles of lichens. The colours of the fore 

 wings of the perfect insects are also equally deceptive, rendering it quite as diffi- 

 cult to perceive the moths when settled upon the trunks of the trees. The hind 

 wings of these moths are, however, very beautifully coloured, being either red or 

 pale blue, with black bands. Catocala fraxini (the great Clifden nonpareil) 

 feeds, in the larva state, on poplar, ash,&c. ; C. nupta L. upon Salix vitellina ; 

 and C. elocata Esper (the claim of which to be considered a native species is 

 questionable) upon willows and elms. Our j%. 1293. represents the last- 

 named species copied from Curtis's British Entomology, pi. 2 17. ; and the generic 



1293 



details, a to , are from C. nupta. a, b, parts of the antenna ; r, spiral tongue ; 

 </, palpus ', e, palpus denuded ;/, the head ; g, one of the ocelli; />, hind leg; 

 i y claws. 



Amongst Coleoptera, the principal species which feed on the willow are, 

 Galeruca capreae, Pyrochroa rubens (on the rotten wood, whilst in the larva 

 state), Melasoma populi and tremula, Balaninus saliclvorus, and Tachyerges 

 salicis ; and, amongst the Hemiptera, ^ x phis salicis L., and Coccus capreae and 

 C. salicis L. 



Some parts of the preceding article have been furnished to us by J. O. 

 Westwood, Esq., by whom the whole has been revised. 



The Study of the Species. The genus Salix has been a stumbling block to 

 botanists from the time of Linnaeus, who observes that so great are the 

 changes effected on the kinds by soil, situation, and climate, that it is difficult 

 to determine whether many of the differences should constitute species, or 

 varieties only. He recommends rejecting the old names and characters, and 

 describing anew the several species accurately, as seen in their natural places 

 of growth. For this purpose, he gives directions for observing the develope- 

 ment of the buds, the situation of the catkins, the form and other circuni 



