486 



NEW YORK STATE MUSEUM 



The large grubs of this giant snapping beetle have been described by 

 Dr Harris as about 2^ inches long, nearly y 2 inch in breadth, flattened, 

 reddish yellow in color. It is frequently found in decaying appletree wood. 



Broad-necked prionus 



Prionus laticollis Drury 

 A thick, fleshy, legless grub about 3 inches long when full grown bores in the roots 

 and stumps of a number of trees. 



This is a very common insect in New York State, though it rarely 

 causes much damage so far as known, for all that the grubs are capable of 

 doing considerable mischief. As a rule we believe their depredations are 

 confined very largely to comparatively valueless forest trees, and therefore 

 this insect is not often brought to the attention of economic entomologists. 

 The operations of this grub being very largely under ground, also enable it 

 to escape notice. The adult beetle is one of the largest native forms, 

 measuring about iyi inches in length and inch or more in breadth. It 

 varies from brown to very dark brown or black. The powerful mandibles 

 are very conspicuous with sharp, cutting edges. The antennae are about 

 half as long as the body. The head is minutely and irregularly punctured, 

 the dorsum o£ the thorax smooth, the lateral portions being punctured and 

 the edges prolonged into two or three prominent teeth. The wing covers 

 are coarsely rugose with several more or less distinct ridges and are usually 

 decidedly broader at the base. The larva of this insect has been recorded 

 as infesting pine stumps, roots of living black oak, oak logs, roots of linden, 

 poplar, oak, chestnut, apple, pine and grapevine. Dr Riley records a case 

 where this species was very destructive to young appletrees in Kentucky. 

 These borers as a rule work within the roots, though Dr Riley states of an 

 allied species, P. imbricornis Linn., that where the root is too small 

 to accommodate the borer, it eats away about one third of the bark and hol- 

 lows out the remainder of the root, thus causing great injury in nurseries 

 The adults are abroad during midsummer. 



Remedial measures. Since the larva of this species works in the roots, 

 it is very difficult to check its operations and there is nothing better than 



