Janmij 18, 1872. ] 



JOUENAL OF HORTICULTURE AND COTTAGE GARDENER. 



53 



bark, often bj* widening it for a little distance before com- 

 mencing to burrow, so that the real opening of the gaUery is 

 some distance from where the little heaf) of out-turned frass 

 lies, which marks its orifice." But what is a sort of nursery 

 for the progeny is a tomb for the parent, for, her life's labour 

 thus completed, the female Scolytus dies at the end of the 

 gallery. The larva; hatch in a few weeks, and form along 

 the inner bark (and also upon the wood sometimes), those 

 curious tracks which have been named " tj-pographs," but are 

 scarcely ever seen quite in their natural form, from the pro- 

 pensity which the different broods have to cross each other's 

 tracks. Some might compare these " typographs " to a map 

 in miniature, on which are delineated a number of rivers and 

 streamlets flowing from a common point. The tracks being 

 filled-up with excrementitious matter as the larvaj proceeds, 

 it is unusual for one to turn round and work back again, 

 though these channels not uncommonly run across each other. 

 The more usual coarse of things with these larvjB is for them 

 to become full-grown in the autumn, when they eat into the 

 «olid wood, and construct each a httle chamber where the 

 Tvinter is passed. And Dr. Chapman points out, that owing 

 to this habit they escape being devoured by birds, for as the 

 bark is loosened in the winter by the effects of rain and wind, 

 any exposed larva; are quickly seized and devoured. In most 

 years, however, a moiety of the brood passes through the 

 course of the larval and pupal states in autumn, and apparently 

 these neither live out the winter as beetles, nor deposit eggs. 

 One instance amongst many others we find of what seems a 

 kind of superfluity in Nature, and like the poet we are half 

 inclined to think sometimes that she is not sufliciently " care- 

 iud of the tj-pe." Dr. Chapman is strong in bis couvictious 

 that females of S. Destructor have nothing to do with healthy 

 trees ; and, therefore, he imagines that the attacks of other 

 insect enemies, or disease in the tree itself have always prepared 

 the way for the inroads of these beetle.s. Felled trees, how- 

 ever, the species will find out, even while they are in the act 

 'Of putting forth shoots ; healthy trees which are rooted in the 

 «oil have a mode of defending themselves from such attacks 

 by pouring out sap into the burrows while they are yet being 

 formed. On the question as to the injuries committed by both 

 sexes of Destructor while visiting trees in search of food. Dr. 

 Chapman does not enter. 



I should not be stating the case fairly unless I add here, that 

 in the opinion of Professor Andouin and some othert, much 

 harm is done by the attacks of the species upon bark when it 

 as in search of food, so that in this way (as is supposed), through 

 the loss of sap, and the mischief done also by the rain enter- 

 ing through the holes which have been gnawed, the trees are 

 prepared for the ravages of the larvte. 



Two species of the Scolytus which are of some interest to the 

 pomologist, are S. Pruni and S. rugulosus. During last sum- 

 mer a correspondent of this Journal forwarded specimens of 

 bark and wood which had been infested by the former ; many 

 of the larvaj were dead, proving that the species is rather 

 delicate, as had been already noted by observers. The burrows 

 «f this species are to be found in Apple, Pear, and Apricot, 

 and in all probability in other fruit trees. Dr. Chapman has 

 found no proof of its having ever committed any positive 

 mischief in our orchards, though it, doubtless, accelerates the 

 ■decay of some trees which, as far as our judgment goes, we 

 shoiild consider healthy, yet some decomposition has secretly 

 set in and is destroying the vitality. In one instance a strip of 

 iealthy bark was found to contain a few incomplete burrows, 

 but the beetles had been annoyed by the presence of a fluid 

 which was manifestly sap exuded from the tree. One marked 

 peculiarity in the burrow of Pruni is, that it often begins in a 

 ■squarish chamber ere it lengthens in a shape like that of 

 Destructor. The males in the latter species make a ver;- short 

 stay in the burrows. In Pruni the males continue in them for 

 some while and devour the excavated material. When of full 

 size the larvie bore into the wood of the tree to the depth of 

 several lines, and the matured beetles do not emerge until the 

 ■end of the June following. 



The other orchard species, rngnlosus, is hardier, and therefore 

 rather more common, and is curious as burrowing occasionally 

 in very slender branches. The opening into the burrow made by 

 the female is not at all hidden, as in some of the other species. 

 This burrow is not much more than an inch in length, and it 

 is lined with comminuted particles taken, not from the bark, 

 but from the wood, so that this " frass " gives an appearance 

 to the gaUery which is not observable in that formed by the 

 Ei>ecie3 previously described. The eggs are laid very evenly. 



and the larvas are irregular in their movements, the tjTpograph 

 being quite distinct in its tracery, except in any case where 

 they are unusually crowded. This species is silent. Destructor 

 and Pruni are able to give a vocal performance, in which the 

 abdomen and wing-cases are concerned. Though not exactly 

 quarrelsome, all the Scolyti are in the habit of giving each 

 other a push with the head, should they como into contact. 

 Perhaps it is a mode of friendly recognition, Uke the custom 

 of rubbing noses which is found amongst some primitive races. 

 On the supposition that these beetles are hurtful Loudon 

 and others have suggested deaUng with them as foUows ; but 

 the advice should, I think, be taken cum grano salis. The 

 advice resolves itself into three particulars. To begin, let us 

 say that you have before a number of suspected trees. With 

 a spokeshave or some fitting tool you pare away the outer 

 bark ; and if on examination there are no traces of burrows or 

 small holes in any tree, then it may be pronounced sound, so 

 far as this insect is concerned. Secondly, assuming that ou' 

 inspection you find traces of larv£E and burrows of the females, 

 then cut down to the wood to make sure, then have the tree 

 feUed, and the bark stripped off and burnt. But allow me to 

 add here, that if this is done during the period of hybernation, 

 unless something is done to the wood itself, there will be an 

 emergence of beetles next summer. Thirdly, trees, especially 

 young ones, which have seemingly been visited by the beetles 

 only for food, must be brushed over with coal tar, which is 

 highly displeasing to the olfactory nerves (possibly) of the 

 females. This may be repeated more than once, and is best 

 done in the spring. Instances have been cited by authors, 

 EngUsh and continental, where the life of many a jn'omising 

 tree has thus been saved. — J. R. S. C. 



GBOUND LEVELLING AND PRACTICAL 

 GAEDEN PLOTTING.— No. 26. 

 Befoke a design is drawn to suit a piece of ground it is 

 necessary to find the superficial dimensions and the general 



outline of the ground on which the design is to be executed, 

 observing accurately at the same time the exact position o f 



