254 HALF HOURS WITH IN^SECTS. [Packakd. 



qucntly drawn to the branches and main shoots of young 

 hickory trees (Carya alba), which were girdled with a deep 

 notch, in such a manner as to induce an observer to believe 

 that the object in view was to kill the branch beyond the 

 notch, and extraordinary as it may appear, this is actually 

 the fact, and the operator is an insect whose instinct was 

 implanted by the Almighty power who created it, and under 

 such circumstances that it could never have been acquired 

 as a habit. The effect of girdling is unknown to the insect, 

 whose life is too short to foresee the necessities of its prog- 

 eny during the succeeding season." 



" This insect may be seen in Pennsylvania during the two 

 last weeks in August and the first week in September, feed- 

 ing upon the bark of the tender branches of the young hick- 

 ories. Both sexes are rather rare, particularly the male, 

 which is rather smaller than the female, but with longer an- 

 tennae. The female makes perforations in the branches of 

 the tree upon which she lives (which are from half an inch 

 to less than a quarter of an inch thick), in which she depos- 

 its her eggs ;'she then proceeds to gnaw a groove of about a 

 tenth of an inch wide and deep around the branch, and 

 below the place where the eggs are deposited, so that the 

 exterior portion dies, and the larva feeds upon the dead 

 wood and food which is essential to many insects, although 

 but few have the means of providing it for themselves or 

 their progeny by an instinct so remarkable." 



"Where this insect is abundant, it must cause much dam- 

 age to young forests of hop-holes by the destruction of the 

 principal shoot." 



A wood engraver plies its trade of scoring the trees be- 

 neath the bark. This is the Scolytus caryce, whose habits 

 have been well described by Mr. Riley. In Illinois, during 

 a period of about ten years, it destroyed "many hundreds 

 of fine young trees." Mr. Bryant writes that " it has sadly 

 thinned my beautiful grove, and bids fair to destroy all the 



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