228 GEOLOGICAL SURVEY OF NEW JERSEY. 



trouble. The numerous types of Rove beetles, sap beetles, 

 fungus beetles, &c., that are always found on dead and dying 

 wood have not been even mentioned. 



A fallen tree in the second season on the ground will occupy 

 an entomologist an entire day in its exploration, and insects in 

 some stage will be found in all parts of it ; and each year brings 

 different forms, adapted to live under the changed conditions 

 until, when the woody mass can be crumbled between the 

 fingers, the minute little Scydmanids and Pselaphids are sifted 

 out over a cloth. 



There is another set of insects that may have the effect of 

 crippling or distorting a tree, as, for instance, the white pine 

 weevil. This attacks the leading shoots of pine, fir and spruce, 

 the larva boring into them and forming large cavities. When, 

 as is usually the case, a number of the grubs are found in one 

 shoot, it withers up and dies, leaving the plant to send out a new 

 leader from another point. That, of course, destroys the 

 symmetry of the tree, and a cripple results, of no value for 

 ornamental purposes in a park and of little use for timber, should 

 that stage be ever reached, for, once the victim of an attack of 

 this kind, the tree seems predisposed to further injury of the 

 same character, so that several leaders may be killed and the 

 tree transformed into a mass of forks. 



Another weevil larva attacks willow in much the same way, 

 save that the infestation is more general, no "leading" shoots 

 occurring in this tree. In fact, quite a number of weevil larvae 

 bore into twigs or branches or live beneath bark, causing local 

 trouble, rather than general effect on the plant attacked. 



The larvae of weevils are somewhat like white, grubs in shape, 

 but much smaller, not so much curved, without the peculiarly 

 rounded anal segment and without legs. The grubs found in 

 chestnuts, hickory nuts and acorns belong to this tribe, and give 

 a good idea of the general appearance of curculio larvae. 



It cannot be insisted too strongly that there is an insect host 

 constantly on the watch to reduce to dust every tree that shows 

 the least trace of nagging vitality, just as there is always ready a 

 group of seedlings ready to take part in the struggle for the place 

 vacated by a dead tree. It is indeed a continuous battle, not only 

 between plant and plant, but between plant and insect, and, in 



