6 
PINETUM BRITANNICUM. 
be the cafe with all the Silver Firs, that their feed feems to be productive only once in three or four years. 
We believe that the experience of feedfmen will bear us out in faying that three out of four confignments of 
feeds of thefe Firs, from one fource or other, proves a failure. Such was the experience of thefe gentlemen 
with the Picea nobilis. It naturally became an objebl of fome intereft to know what was the infebt which 
occafioned this havoc. This was not difficult to afcertain. A cone placed in a clofecl glafs veffel in due 
time brought out hundreds of a fmall hymenopterous infebt belonging to the genus Megajligmus, and now 
named Megajligmus Pini , allied to the Chalcidites (fmall Ichneumon flies), of which the woodcut [fig. 19] 
is a highly magnified reprefentation. The fort of calyx out of which the abdomen fprings is peculiar to the 
tribe of infebts to which this fpecies belongs. Thefe flies are generally fuppofed to be entirely parafitical ; 
but the fabt of immenfe numbers coming out of the cones without any admixture of other infebts, and 
from no trace of the Akin of the facrificed larva being to be found in any of the empty kernels from which 
the infebt emerges, this would feem to be unlikely, fo far at leaf! as regards this fpecies, as it is highly 
improbable that all the larvae could have been ichneumonifed. It thus appears 
reafonable to fuppofe that the infect which lays its egg in the feed is the Mega¬ 
jligmus which afterwards appears; and it follows as a corollary that it is 
fimply a vegetable feeder, and that the whole of the fpecies, of the family of 
Ichneumonidae, are not parafites. Similar exceptions to the general eco¬ 
nomy of a family have been found in other groups. The converfe of what 
takes place here has been found in the Cynipidce or gall-flies, which live in 
gall-nuts or morbid excrefcences caufed by their own prefence in the leaves 
of oaks or other plants. Some of thefe have been fatisfabtorily {hewn to be 
parafitic in other infebts. Subfequently to Murray and Beardfley’s expedi¬ 
tions, various importations have taken place, chiefly from the collections of Mr 
Lobb or Mr Bridges, two affiduous collebfcors, who have done much to fupply this country with the 
cream of Californian vegetable produbtions. The fame drawback which attended previous efforts has 
accompanied theirs: the feed is feldom free from the attacks of the Megajligmus Pini; and when one is 
found in a cone, it is fafe to affume that fcarcely a Angle productive feed will be found in it. The careful 
and afhduous mother leaves not a found feed unfupplied with an egg ; nor does fhe wafte one upon a feeble 
or unproductive embryo. Seedlings of this tree, therefore, ftill are, and are likely to continue, fcarce and 
valuable. 
Properties and UJes. —For decoration no tree can be finer; but fo far as we yet know, its ufes go no 
further. Its timber was ftated by Douglas to be of excellent quality. This is now known to be a miftake. 
It is white, foft, and nearly worthlefs. 
Ctdture. —No particular mode of cultivation is required for it. It is very hardy, having paffed through 
the winter of 1860-61 unfcathed. There appears, therefore, no reafon for the precaution which is ufually 
taken of fowing the feeds in a cold frame; a precaution, no doubt, taken by cultivators more out of 
regard to the high price and value of the feed than from any neceffity or fpecialty in its growth. We are 
not aware how it thrives in undrained wet foil. The common Picea pedlmata likes a good deal of moifture, 
and we fhould not be furprifed that P. nobilis had fimiliar predilections; but we have never feen it growing 
in fuch conditions. It is generally placed in fome fpecially well-drained fpot near the manfion, where it can 
be readily reached, and feen, and admired. It feems, however, to thrive well everywhere, and is now pretty 
generally diftributed in this country. 
The plants raifed from home-grown feeds are not fo ftrong and healthy as plants grown from feeds 
brought from their native country; and it has been obferved that a large proportion of the feedlings from 
home-grown feeds foon become difeafed, the leaves firfl: decaying at the tips and gradually becoming wholly 
dead [figs. 20 and 21]. The tips of the leaves firfl; fhew it; they begin to wither, and gradually the decay 
fpreads 
Fig. 19. 
