1638 ARBORETUM AND FRUTICETUM. ‘PART III. 
from which it will be impossible entirely to extricate them, till both the male 
and female plants of each sort have been cultivated together for a number of 
years in the same garden. Judging from the plants in the London nurseries, 
and in the arboretums of the Horticultural Society and Messrs. Loddiges, we 
think that all the kinds now in actual cultivation in Britain may be included 
under the heads of P. lba, P. trémula, P. nigra, and P. balsamifera, 
Poplars, from their rapid growth and great bulk, are liable to have their 
branches broken off by the wind ; in which case, if care is not taken to protect 
the wound from the weather, the water enters, and the trunk soon rots and be- 
comes the prey,of insects, which in their turn are fed on by birds. The larve of 
a number of moths live on the leaves of the poplars, such,as Tértrix populana, 
Bombyx populi, Cerira vinula, Smerinthus pdpuli, S. ocellatus (the eyed 
hawk moth), Anacampsis populélla, and a number of others, some of which 
will be noticed under particular species. The larve of Céssus Lignipérda 
(see p. 1386.), of Aigéria crabroniférmis (see Mag. Nat. Hist., iv. 445.), and 
of some others, live on the wood. The larva of the puss moth (Cerura vinula) 
is one of the few caterpillars that are known to have the voluntary power of 
communicating electricity. An interesting account of the manner in which 
this was discovered by a naturalist in Selkirkshire, is given in the Magazine of 
Natural History, vol. iv. p. 281. The larva of this insect is very common ‘on 
poplars and willows in Switzerland, where the pupa often remains two full 
years, before it assumes the perfect state. (Jdid., viii. 558.) Pépulus gree‘ca 
affords food to this moth, to the poplar hawk moth (Smerinthus pdpuli), to 
the kitten moth (Cerura farcula), to the pebble prominent moth ( Notodénta 
ztczac), and to various species of Clostéra, (the chocolate-tipped moths), which 
feed exclusively on the poplar and willow. The larva of Smerinthus pdpuli 
(Mag. Nat. Hist., viii. 629.) is very common both on poplars and willows, 
and often strips them entirely of their foliage; the moth of this species is 
seldom seen, as it flies but little, and only during the night. The larva of 
Smerinthus ocellatus is common on willows and poplars from July to the end 
of September, and the fly does not usually appear till the following spring. 
It is stated of this insect, that a female produced young without having any 
connexion with the male; from which it would appear that in certain Lepi- 
déptera a single pairing can render fertile more than one generation, as well 
as in the case of the A’phides. (Mag. Nat, Hist., viii.557.) Trochilium api- 
forme (the hornet hawk moth) and Aigéria asiliférmis feed on the Lombardy 
poplar, on which the larva may be found in May and June, early in the morn- 
ing ; the fly almost invariably mounts to the top of the trees soon after sunrise. 
(Zbid., p. 555.) .The splendid European butterfly (not yet detected in Great 
Britain), Limenitis populi, frequents the aspen. The caterpillar, also, of the 
fine Camberwell beauty, or, as it used to be called, the poplar butterfly, feeds 
on the poplar. Both poplars and willows, when the trunks begin to decay, 
are attacked by the jet ant (Formica fuligindsa), more especially in France, 
and on this insect that very shy bird, the hoopoe chiefly lives. Among the 
coleopterous insects, Rhynchites pdpuli, Chrysoméla pépuli and C. trémule, 
Sapérda poptlnea, and Orchéstes pdpuli, one of the flea weevils, feed on the 
leaves of poplars. Notices of all the preceding insects, and of various others 
which attack the poplar and the willow, will be found in the Magazine of 
Natural History, vols. i. to ix. inclusive. Various epiphytical fungi are found 
on the poplar, some of them on the leaves, and others on the bark of the 
branches or trunk; such as Sclerotium poptlinum Pers., Erysiphe adinca 
Link and E. populi Link, Erineum atreum Pers., Urédo poptlina Pers., 
and U. ovata Straus. Some others will be noticed under particular species ; 
and the greater part are included among the Cryptogimia of our Encyclo- 
pedia of Plants, where several of the species are figured. 
¥ 1. P.a’tBa L. The white Poplar, or Abele Tree. 
Identification, Lin. Sp., 1463. ; Willd. Sp. Pl., 4. p. 802.; Smith Eng. Bot., t. 1618.; Eng. Fl., 4. 
p. 243. ; Hook. Brit, F'l., ed. 2., p. 432.; Mackay Fl. Hibern., pt. 1. p. 254.; Raii Syn., 446.; Ger. 
Enum., 1486. ; Bauh. Hist., 1. p. 2. fig. 160. 
Synonymes. P. Alba latifolia Lob. Ic., 2. p. 193. fig..1.; Populus No. 1634. Hall. Hist., 2. p. 308. ; 
P. major Mill. Dict., 8. No. 4.3 P. nivea Wiltd. Arb., 227.; P, alba nivea Mart, Mill. The name 
