Dec, 1846.] 133 



from the eggs, and their living, as all acknowledge, on the sap of 

 the roots of plants, I was led to think that the constant drain of 

 sap required to nourish so many thousands of grubs, of from a 

 quarter of an inch to an inch in length, must be more than a tree 

 could live through, and yield good fruit. I was confirmed in this 

 opinion by an experiment made by J. B. W., New York, and 

 published in the November number of the Horticulturist, page 

 227. The method prescribed to renovate an outcast, is to dig a 

 trench four feet wide and twenty inches deep, around the tree, 

 leaving a ball of earth six feet in diameter, and then to fill the 

 trench with rich earth and compost. The author states that the 

 experiment succeeded, and that in three years the tree was in a 

 flourishing condition, and yielded fine fruit. The writer attributes 

 the change to the new and rich soil with which he supplied the 

 tree. I argue, that on cutting off the larvae of the Cicada, which 

 he did when he cut off so large a portion of the roots, he removed 

 the real disease, and the tree was then in a condition to take ad- 

 vantage of the congenial soil placed around it ; and new life was 

 given to roots and branches. 



Under this impression, I superintended a similar experiment on 

 a pear tree that had been declining for years, without any appa- 

 rent cause, and agreeably to my expectations, I found the larvae 

 of the Cicada in countless numbers clinging to the roots of the 

 tree, with their suckers piercing the bark, and so deep and firmly 

 placed, that they remained hanging for half an hour after being 

 removed from the earth. From a root a yard long, and about an 

 inch in diameter, I gathered twenty-three larvas ; they were of 

 various sizes, from a quarter of an inch to an inch in length. 

 They were on all the roots that grew deeper than six inches below 

 the surface. The roots were unhealthy, and bore the appearance 

 of external injury from small punctures. On removing the outer 

 coat of bark, this appearance increased, leaving no doubt as to 

 the cause of the disease. 



The larvae were enclosed in a compact cell of earth, with no 

 outlet except that in immediate contact with the root, and as 

 there were no galleries or holes leading from these cells, I infer 

 that the grubs never leave the roots they first fasten on ; which 

 may account for the great difference of size; the small ones being 

 starved specimens of the same brood : though I am inclined to 

 believe that there are two species, differing sufficiently in size to ac- 

 count for the discrepancy in the size of the larvae now found. I 

 noticed this difference in 1817, and again in 1834 : the note of 

 the smaller variety, or species, is much shriller than that of the 

 larger, and will never be mistaken when noticed. 



The Cicado is too well known to need a description here; I 

 will therefore only notice its habits as they have fallen under my own 

 observation, and make a few extracts from an article published in 



19 



