184 INSECTS INJURIOUS TO VEGETATION. 



come forth only once in seventeen years, while those of other 

 swarms may appear, after equally regular intervals, in the 

 intervening period, in other places. 



The seventeen-year Cicada ( Cicada septendecim of Linnaeus), 

 in the winged state, is of a black color, with transparent wings 

 and wing-covers, the thick anterior edge and larger veins of 

 which are orange-red, and near the tips of the latter there is a 

 dusky zigzag line in the form of the letter W ; the eyes when 

 living are also red; the rings of the body are edged with dull 

 orange ; and the legs are of the same color. The wings ex- 

 pand from 2J to 3^ inches. 



In those parts of Massachusetts which are subject to the 

 visitation of this Cicada, it may be seen in forests of oak about 

 the middle of June. Here such immense numbers are some- 

 times congregated, as to bend and even break down the limbs 

 of the trees by their weight, and the woods resound with the 

 din of their discordant drums from morning to evening. After 

 pairing, the females proceed to prepare a nest for the reception 

 of their eggs. They select, for this purpose, branches of a 

 moderate size, which they clasp on both sides with their legs, 

 and then bending down the piercer at an angle of about forty- 

 five degrees, they repeatedly thrust it obliquely into the bark 

 and wood in the direction of the fibres, at the same time put- 

 ting in motion the lateral saws, and in this way detach little 

 splinters of the wood at one end, so as to form a kind of fibrous 

 lid or cover to the perforation. The hole is bored obliquely to 

 the pith, and is gradually enlarged by a repetition of the same 

 operation, till a longitudinal fissure is formed of sufficient 

 extent to receive from ten to twenty eggs. The side-pieces of 

 the piercer serve as a groove to convey the eggs into the nest, 

 where they are deposited in pairs, side by side, but separated 

 from each other by a portion of woody fibre, and they are 

 implanted into the limb somewhat obliquely, so that one end 

 points upwards. When two eggs have been thus placed, the 

 insect withdraws the piercer for a moment, and then inserts it 

 again and drops two more eggs in a line with the first, and 

 repeats the operation till she has filled the fissure from one end 

 to the other, upon which she removes to a little distance, and 



