200 



NATURAL HISTORY. 



The limb which he cuts off is sometimes only a foot in length, and is con- 

 sequently quite light ; sometimes ten feet long, loaded with leaves, and 

 very heavy. A man, by carefully inspecting the length of the limb, the 

 size of its branches, and the amount of foliage growing upon them, could 

 judge how far it should be severed to insure its being afterwards broken 

 by the winds. But this worm is imprisoned in a dark cell, only an inch or 



two long, in the interior of the limb. How is 

 it possible, therefore, for this creature to know 

 the length and weight of the limb, and how 

 far it should be cut asunder ? A man, more- 

 over, on cutting a number of limbs of different 

 lengths, so far that they will be broken by 

 the winds, will find that he has often miscal- 

 culated, and that several of the limbs do not 

 break off as he designed they should. This 

 little worm, however, never makes a mistake 

 of this kind. If the limb be short, it severs 

 all the woody fibres, leaving it hanging only 

 by the outer bark. If it be longer, a few of 

 the woody fibres on its upper side are left uncut in addition to the 

 bark. If it be very long and heavy, not more than three-fourths of the 

 wood will be severed . . . With such consummate skill and seemingly 

 supcrterrestrial intelligence does this philosophical little carpenter vary his 

 proceedings to meet the circumstances of his situation in each particular 



Fig. 188. — The shining chestnut-borer 

 (Arrhopalus) , enlarged. 



case 



Some of the long-horns are peculiar in their shapes. In some the first 

 pair of legs are greatly lengthened ; in others, the antennae may be five or 

 six times the length of the body. Some are dull-colored, others are decked 



with the brightest hues, laid on 

 in the most peculiar patterns. 

 All possess organs for producing 

 a noise, some of a squeaking, 

 others of a rasping character. 

 These noises are all produced 

 by rubbing one part against 

 another, much as in the crickets 

 and locusts, already alluded to. 

 Sometimes the wings, sometimes 

 the legs, and sometimes the 

 rin2;s of the thorax, are the parts 



Pine-tree borers (left, Orthosoma cylindricum; ° , , 



right, Prionus laticoiUs). concerned, and a microscopic 



Fig. 189. 



