CHAP. cm. 5AL1CA CE/E. ^'aYiX. 1483 



moist ground, highly favourable in itself for the growth of osiers, planted it ; 

 and, after a few 3'ears, the osiers had disappeared, he hardly knew how. 

 It was planted a second and even a third time, and the plants always dis- 

 appeared. " My attention," says the writer, " being now strongly drawn 

 to the subject, I discovered that which I ought to have perceived half a 

 century sooner ; namely, that Nematus capreae, favoured by the peculiar lo- 

 cality, was the cause of all this devastation. The spot is low, moist, shut 

 in by wood, and very near the southern limit of England. The species of 

 willow planted was chiefly one of those with broad leaves, woolly underneath 

 (probably S. caprea L.). The warmth of the situation, and the nidus for eggs 

 afforded by these woolly leaves, were, I presume, the combined cause of the 

 insect being so remarkably attracted to this spot. Some of the plants were 

 of a species with smooth narrow leaves (probably S. triandra L.) : these es- 

 caped much longer than the others, but still they did not escape eventually, as 

 they were also attacked by another caterpillar. I introduced both red and 

 black ants, and put some of the caterpillars into their nests ; but the ants 

 disregarded them altogether. Having, although thus slowly, ascertained the 

 true state of things, the ground was once more cultivated, and was planted 

 with apple trees. As there happens to be no insect there which much attacks 

 these, they thrive very well. The distance at which apple trees are planted 

 is, also, less favourable to the propagation of vermin, 1 have communicated 

 all this detail in order to show the importance to individuals of attending to 

 such seemingly trifling matters. Many a plantation, &c., fails in an apparently 

 inexplicable manner. A scientific investigation would, in numerous cases, 

 disclose the truth, and prevent farther loss. Had a person acquainted with 

 entomology been jn-oprietor of this osier ground dO years since, he would 

 speedily have discovered the truth, and might have saved 200/. or more to 

 himself and his successors." (Alag. Nat. Hist., vii. p. 423.) 



The Chrysomela (Phas'do«) vulgatissima L. is another species which is 

 occasionally injurious to one of the narrow-leaved species of willow. This is 

 a pretty little insect, of a shining blue or green colour, and of an oblong-oval 

 form, about ^ in. in length, which is found, during the winter months, in great 

 profusion under the loose bark of willows, growing in damp localities. It 

 deposits its eggs upon the young leaves ; and the larviE, when hatched, form 

 little associations, feeding together in regular rows, the heads of the second row 

 touching the tails of the first. In this manner they proceed from the base 

 to the extremity of the leaf, which they soon strip of its parenchyma. Thev 

 then attack the next leaf; and so on, until they are full grown, when thev 

 descend into the earth, and assume the pupa state ; shortly after which they 

 undergo the change to their last and perfect form. 



The leaves of some species of willows are also infested with galls, which 

 are the production, not of a species of Cynipidae, but of one of the Zfenthredi- 

 nidae (Nematus intercus Panzer Fauna Ins. Germ., 90. fig. 11.; or the 

 Tenthredo salicis pentandrae Villars). The larvae of this insect, instead of 

 feeding externally upon the leaves of the willow, is enclosed in a gall, upon the 

 substance of which it subsists, and within which it undergoes all its changes. 

 Mr. Westwood's species Nematus gallicola (described by Mr. Stephens, ///jm^ 

 Brit. Ent., vol. vii. p. 3G.), and the Euura Cynips of Newman {Ent. Mag., 

 No. 18. p. 260.), also reside in galls; whilst the larvae of Nematus saHcis of 

 Saint Fargeau, and of the N. capreae, are external feeders. 



Among the Lepidoptera, the caterpillars of nearly all the species of moths 

 belonging to the genus Cerura (puss and kitten moths) feed upon different 

 species of willow ; and also, occasionally, the larva of the buff-tip moth(PygEeVa 

 bucephala Step//.). Brepha Parthenias (the orange underwing) feeds upon 

 poplars and willows; and Notodonta ziczac (the pebble prominent moth) upon 

 the same : Leiocampa dictas^a and L. dictaeoides (the swallow prominent moths), 

 Ptilodontes palpina (the pale prominent moth), Gastropacha quercifolia, &c., 

 occasionally upon willows; and the larva of Orthosis upsilon Stepfi. beneath 

 the bark of old willows and poplars. 



