8 APPLE-ROOT BLIGHT EXCRESCENCES DESCRIBED. 



have come under my notice, the main root of the young tree 

 was half an inch in diameter, half a span below the surface, at 

 which point it was two-thirds surrounded by an excrescence 

 two inches in length and three inches in diameter and height, 

 and connected to the root by a neck much smaller than its base. 

 (The accompanying figure is a view of 

 the back of this excrescence, reduced to 

 one-fourth its actual size, and one of the 

 small fibrous roots, with an excrescence 

 thereon. The original specimen is pre- 

 served in the Entomological department 

 of the Museum of the State Agricultural. 

 $ociet}\) It is of an irregular, knobbed 

 form. Its surface is of the same yellowish-brown color as the 

 bark of the root, and is everywhere crowded with little round 

 elevations, from the size of a mustard se^d to that of a buck 

 shot or a small pea. On cutting one of the projecting knobs, it 

 is found to be of a very hard, woody texture, and without any 

 cavities in its center. Upon the main root, between this and 

 the surface of the earth, was a second similar excrescence, but 

 smaller; whilst upon several of the small capillary fibres were 

 similar tubers, from the size of a pea to that of a bullet. 



These excrescences are doubtless formed in much the some way 

 that galls and other morbid enlargements in the structure of vege- 

 tables are produce.d. The parent insect insinuates herself down- 

 wards along the side of the root, as it would appear, at the close 

 of autumn, and there deposits her stock of eggs, and perishes. 

 These eggs hatch when the ground becomes warm the following 

 spring, and the young lice insert their beaks into the bark of the 

 root to extract their nourishment therefrom. Their punctures 

 produce a kind of irritation, which causes an increased flow t)f 

 fluids to the spot where they are located. This excessive amount 

 of sap thus diverted to this part occasions an increased growth of 

 the w r ood, and results in the enormous development which we 

 have witnessed. As in other cases in this family, these lice pro- 

 bably continue to multiply without any intercourse of the sexes 

 until autumn, when w r inged individuals are developed, which 



