PERIODICAL CICADA. 127 



ficient to check, materially, the growth of the branch. In such cases 

 the twigs grow so rapidly that, in the course of the month which inter- 

 venes between the time of the laying and the hatching of the eggs, the 

 wound heals completely over, the tent of splinters is nearly or quite 

 over grown, and the young insects never emerge from the eggs, being 

 enclosed in a living sepulchre. 



LARVAL HISTORY. 



Of the protracted subterranean life of these insects in their larva 

 state, of the nature of their food, the depth to which they usually pene- 

 trate, and the extent of their underground migrations, we know almost 

 uothing. The following is a condensed statement of the past record 

 upon this subject : 



In the year 184:6 Miss Margaretta H. Morris, of Germantown, Penn., 

 found a number of locusts in their larva state, and varying from a quar- 

 ter of an inch to an inch in length, attached to the roots of some lan- 

 guishing pear trees. But if this is their habit, it is remarkable that no 

 similar observations have been made by others. And the statement 

 that an insect so regular in its development as the Cicada was found of 

 such ditierent sizes, would render the identity of the insect question- 

 able, were it not for the well known accuracy of this lady in her ento- 

 mological observations. 



Mr. R. W. Kennicott, of West Northfield, Illinois, wrote to Dr. 

 Fitch that in following down a foot or more, in the month of Novem- 

 ber, the roots of several trees and shrubs, the twigs of which had been 

 badly cut to pieces by the locusts of the previous year, he could find 

 no trace of the insects. But this is only negative testimony, and the 

 insects, at this period, must have been so small that they might have 

 been easily overlooked. 



Dr. Gideon B. Smith, of Baltimore, who made extensive observations 

 upon these insects, held the opinion that these grubs subsist exclusively 

 upon the moisture which exudes from the surface of the vegetables radi- 

 cles which permeate the earth. 



He says, "It takes its food from the surface of these roots by means 

 of three exceedingly delicate capillaries or hairs which project from the 

 tube of the snout, and sweep over the surface, gathering up the minute 

 drops of moisture. This is its only food. The mode of taking it can 

 be seen with a good glass." 



I have no means of knowing the method, or extent, or accuracy of 

 Dr. Smith's observations, but if the above account is correct, the way 

 in which this insect takes its food is as anomalous as many other por- 



