THE PRACTICAL ENTOMOLOGIST. 



47 



[From the Journal of Commerce.] 

 Apple-tree Borers. 



The Practical Entomologist, published gratui- 

 tously, at Philadelphia, is, so far, worthy of high 

 commendation. It contains a great deal of just the 

 kind of information which farmers, horticulturists 

 and nurserymen need, without any mark of selfish 

 motives. We hope it may receive such encourage- 

 ment, by advertisements or contributions, as will 

 enable it to enlarge; for it is too small for a monthly 

 devoted to so important a science. The last num- 

 ber is occupied by a treatise upon borers, by Benj 

 D Wa sh, of Illinois. His account of the species 

 ot apple-tree borer which is most common in the 

 Eastern and Middle States (Saperda bivittata), is 

 the best which we have seen. Nevertheless, our 

 tamihanty with this pest warrants us in takin<r ex- 

 ception to on« or two statements. We have literally 

 seen thousands of them; while Mr. Walsh says it 

 IS the Buprestis borer ( Chr>/sobothris femora fa) that 

 prevails in the Mississippi valley, and the other spe- 

 cies does not exist in his neighborhood. We con- 

 clude, therefore, that the slight errors into which 

 we think he has fallen, are copied from others whose 

 accuracy is not equal to his own. 



We do not believe that the larva, " as it approach- 

 es maturity, strikes off into the heart wood " On 

 the contrary, its movements seem to be confined to 

 the sap wood unless there be some particular reason 

 for leaving it. In small trunks or roots, it does not 

 get room enough without encroaching upon the 

 heart; and, when crowded out from one side of a 

 tree by the holes of its neighbors or predecessors, 

 or by the occurrence of dead wood, it may strike 

 through the heart to another location. Its last and 

 largest cavern must be excavated near the bark as 

 otherwise the beetle into which it changes would be 

 unable to escape. . 



We do not think that this borer ever opens a hole 

 in order to get rid of his castings." We have 

 found them, in every stage of their existence, with- 

 out any opening whatever to the outer air They 

 crowd certain parts of their excavations with chips 

 We opine that, where the covering is thin, cracks 

 are opened by the swelling of these chips when 

 moistened. They seldom occur except at the time 

 of sap rising in early spring. We may allow, in- 

 deed, that, when these cracks have once been formed 

 Iresh chips are often forced out at them, but they 

 are evident rents and not gnawed holes. The hole 

 at which the beetle escapes is readily distinguished 

 from them by being higher up the trunk and cir- 

 cular, as if made by a small bullet. There can be 

 no more absurd truism than was uttered at one of 

 the meetings of the American Institute Farmers- 

 Club, to the effect that it is as well to plug these 

 holes up as to cut them open. Of course, after the 

 horse IS stolen, it does just as much good to tie up 

 the halter as to lock the stable door. 



But Dr. Fitch, who is well acquainted with this in- 

 sect, asserts as follows of its larva : — 



It takes up its abode in the sapwood, feeding 

 upon and consuming the softwood, hereby forming 

 a smooth round flat cavity, the size of a dollar or 

 larger, immediately under the bark. It keeps its 

 burrow clean by pushing its excrement out of a 

 small crevice or opening through the bark, which 

 It makes at the lower part of its burrow, and if this 

 orifice becomes clogged up it opens another. This 

 excrement resembles new fine saw-dust, and enables 

 us readily to detect the presence of the worm by 

 the little heap of this substance which is accumu- 

 lated on the ground. * * * When the worm is 

 half-grown or more it gnaws a cylindrical retreat 

 for itself upwards in the solid heartwood of thetree. 

 This hole runs slightly inwards, towards the centre 

 of the tree, and then outwards, so that when it is 

 completed its upper end is perforated through the 

 sapwood and is only covered by the bark. (iV. Y. 

 Reports, I. pp. 14 — 5.) 



Subsequently Dr. Fitch modified the above state- 

 ment, so far as regards the larva's opening a hole 

 for itself in early life in order to get rid of its cast- 

 ings, as follows : — 



The cavity [under the bark] is almost invariably 

 found stuffed full and densely packed with the saw- 

 dust like castings or chips of the worm, a small 

 quantity of which is commonly protruded to the 

 outside of the bark, sometimes through a natural 

 crack formed by the bark becoming dead, dry and 

 contracted, sometimes through one or more small 

 orifices which appear to be gnawed by the worm. 

 But I have met with many instances where none of 

 this powder was protruded, the blackened and 

 slightly depressed surface of the bark being the 

 only indication of the mischief that was going on 

 beneath. {N. Y. Reports, II. pp. 4—5.) 



From what I know of the habits of allied insects, 

 I incline to believe that the Journal of Commerce 

 is right in asserting that this larva never purposely 

 opens a hole in order to get rid of its castings, and 

 that Dr. Fitch is right in as.serting that, in the 

 latter part of its larva life, it bores into the solid 

 heart- wood. 



THE CHINCH BUG. 



Remarks, by B. D. W.-The author of the above 

 IS correct in surmising that I have no personal ac- 

 quaintance with the habits of the Two-striped Borer. 



An article appeared some time ago in the Wau- 

 kegan (111.) Gazette, from the pen of D. H. Sher- 

 man, of that place, claiming that he had made a 

 discovery by which farmers, if they but followed 

 his advice, could readily protect their grain from 

 the Chinch Bug. The discovery was, that the eggs 

 were deposited by the parent bug in the "fuzzy" 

 or blossom end of the kernels of grain, and conse- 

 quently, by properly manipulating the seed and de- 

 stroying the eggs, the future ravages of the bug 

 would be prevented. To those who knew anything 



