OAK-ROOT BORERS. 51 



In point of fact, however, in its connection with this tree the beetle shows a sur- 

 prising modification of its recorded habits. Its larva is found, not in the stem of the 

 mature tree so justly celebrated for its strength and toughness, but always in the 

 root of infant trees, and usually in degenerate highland varieties of Quercus virens, 

 or of its relatives, Q, aqtiatica and Q. catesbcei. 



The mother beetle selects small saplings as a place of deposit for her eggs, which, 

 are laid in the foot, or collar, of the tree, just below the surface of the ground. 

 How long a larval existence the insect has is not known, but it must extend over 

 several years, since the roots occupied by these larvse grow to a large size, while at 

 the same time they show an entirely abnormal development and become a tangle of 

 vegetable knots. In fact, the entire root in its growth accommodates itself to the 

 requirements of the borer within. Very few new roots are formed, but the old roots 

 excavated by the larva are constantly receiving additions of woody layers, which 

 are in turn eaten away and huge iiattened galleries are formed, which are for the 

 most part tightly packed with sawdust. 



The beetle thus becomes, not the destroyer, but the parasite of the tree, and lives 

 in a domicile, which may not improperly be termed a gigantic root-gall. The efifect 

 on the tree is to kill the original sapling, which becomes replaced by a cluster of in- 

 significaut and straggliog suckers, forming perhaps a small clump of underbrush. 

 In many cases the branches and leaves are barely sufficient to supply the materials 

 for sluggish growth, and the entire strength of the plant goes toward the formation 

 of a root plexus, out of all proportion to the growth above ground, and plainly de- 

 signed to repair the ravages of the borer. 



The Mallodon borers are very abundant in South Georgia and Florida, and as a 

 result of their attacks, vast tra;cks which might otherwise have become forests, en- 

 riching the ground with annual deposits of leaves, are reduced to comparatively bar- 

 ren scrub, in which the scattered oak bushes barely suffice to cover the surface of 

 the sand. 



Many a new settler, seeing his sandy hill-side covered only by insignificant oak 

 bushes, and anticipating easy work in converting the wilderness into a blooming 

 garden of orange-trees, has been grievously disappointed to find before him no light 

 task in clearing from the soil these gnarled and tangled roots. In fact the great 

 strength and weight of the southern grubbing-hoe appears no longer a mystery when 

 one contemplates the astonishing pile of "grub roots" which in vigorous hands it 

 will extract from a few square rods of apparently unoccupied soil. 



The results of the work of this beetle are very plainly visible around Savannah, 

 and especially on Tybee Island, where Mr. George Noble first drew our attention to 

 it; while Mr. Hubbard has carefully studied its work, as here recorded, in Florida. 

 {Eiley's report, 1884.) 



The genus Mallodon contains species of large size with the sides of the prothorax 

 armed with numerous small teeth. The head is comparatively large, the eyes 

 strongly granulated, distant, transverse, feebly emarginate. The antennre are slender, 

 not exceeding half the length of the body in the male and shorter in the female. The 

 sexual differences are worthy of note. The prothorax in the male is nearly quadrate, 

 densi'ly punctured, with smooth separate facets, while in the female it is narrowed 

 in front, more coarsely punctured towards the sides, and uneven on the disk. 



The present species is distinguished by the decidedly serrate prothorax, while the 

 tibii© are densely ciliated on the lower edge. It is dark brown, almost black. 

 Length, 45 to 55^™, (1.7.5 to 2.25 inches). It inhabits Florida, Arkansas and Texas. — 

 (Horn.) 



Larva. — Body as large and thick as one's forefinger. It closely resembles the larva 

 of Orthosoma hrunneum* in general appearance and proportions, but considerably 

 thicker. Shape of the prothoracic segment and size of the head and shape of the 



* 1 have no larva of Prionus laticolUs with which to compare it, and which it may 

 more closelv resemble than Orthosoma. 



