" From this table the condition of the trees will be seen previous to beinj? sub- 

 milted to my plan. Now, before we proceed to speak of tieatiueut, there are two very 

 important stages to be settled: (irst, is tlie iree diseased before it is attacked by the 

 Scolytus? and, in the second place-, does the attack of the Scolytus prove injurious to 

 the tree? 



"As regards the condition of the tree, I think we hid i'l the Garden of the Royal 

 Botanic Society a sufficient number of sickly ones to enable us to come to a very fair 

 conclusion. The number first planted was 242; in 1843, 67 had a healthy appear- 

 ance; 66 were attacked by the Scolytus, 10 by the l.nviB of Cossus Ligniperda ; 

 99 had sickened or died, and had been cut down, 62 of which sprouted again, and 37 

 quite perished. With respect to the condition of the healthy ones, the embankment 

 equally adjoined them in places; but of the 18 that were allotted to me no embank- 

 ment existed ; therefore this could not have been the cause (if Nos. 2, 3, 7, 9, 11 13 

 15, 16 and 18 having such a sickly appearance; and if it arose from their roots pene- 

 trating a gravelly soil, the mere fact of partially barking could by no possibility restore 

 them to health and vigour. I think we may fairly say that this is a self-evident pro- 

 position. And, again, what is the appearance of a tree languishing from defective 

 soil? We see it first in the leaf, which is small and unhealthy in coluur; the termi- 

 nal branches next gradually decay, piece after piece breaking away, until the longer 

 branches present what is generally called a 'stag-horned appearance,' and the tree 

 finally perishes ; but this is not brought about in a day or a week, being usually the 

 affair of some few years, for as long as nutriment can be obtained the crippled tree 

 exists in its withering and fading condition. But when we find a tree dead, with ter- 

 minal branches profuse and perfect, we certainly, under ordinary circumstances 

 should not say that tree had died from defective nutrition in the soil, but that, from 

 some cause or another, it had suddenly, as it were, come to an untimely end ; and 

 such a tree we had in the Gardens; I watched it in its beauty, and in three years saw 

 it cut down and carried away dead ; but what a sight met our view on removino- the 

 bark ! — the surface of the trunk, as many gentlemen will remember (for I exhibited a 

 piece of it, 3 feet long, before this Society), was beautifully scored by the lateral tubes 

 of the Scolytus larvae ; and we reckoned that this solitary tree gave birth to no less 

 than the prodigious number of 280,000 perfect insects! Well may we be transfixed 

 •with astonishment; but the greater wonder is that an elm should still be found to 

 grace our ornamental parks. I may now fairly presume to state that the IS sickly 

 trees were not in the least suffering from defective nourisliment at the roots, nor had 

 their stems been embanked in soil ; and yet many of them were evidently dying; but 

 one thing was very apparent, namely, that in proportion to the sickly condition of the 



tree so we found the increase of Scolyti. And this leads us to the second question, 



Does the attack of the Scolytus prove injurious to the tree ? 



"The Scolytus destructor is known to many present; it is a small dark beetle, be- 

 longing to the family Bostricidae of Leach. When the first warmth of spring sets in 

 the perfect insect escapes from beneath the bark, by eating its way out; the female 

 soon after selects a tree for the purpose of depositing her ova ; she commences her per- 

 foration always beneath a little projecting piece of bark at the upper end of a crack; 

 she bores iuwards and upwards until on the surface of the alburnum, when she ascends 

 direct; the lube thus formed is from 2 to 3^ inches in length, flhs of a line in diame- 

 ter, and of equal size throughout, except at a short distance from its entrance, where 

 a small cavity is usually found sulficiently large to allow the parent insect to turn ; on 



