VOL. LIV.] PHILOSOPHICAL THANSJkCTIONS. JOI 



remarkable; but at certain periods, of 14 or 15 years distance, they come forth 

 in such great swarms, that the people have given them the name of locusts. 

 About the latter end of April these cicadae come near the surface: this is known 

 by the bogs routing after them. They creep out of the ground, near the roots 

 of trees, in such numbers, that in some places the earth is full of holes, like a 

 honey-comb. Their first appearance is a hexapode (an ill-shapen grub) with six 

 feet. This is their middle or nymph state: they creep up every thing near them, 

 and fix their claws fast on the shrubs, and bark of trees: then the skin on its 

 back bursts open, and the fly comes forth, disengaging itself by degrees, leaving 

 the case or exuviae behind, in the exact shape in which it was before occupied. 

 At first coming out the cicadae are all white, with red eyes, and seem weak and 

 tender ; but next day they attain to their full strength and perfection, being of a 

 dark brown colour, with 4 finely veined transparent wings, as will be better seen 

 than described, by the specimens, fig. a, pi. 4. 



They come forth out of the ground in the night; being then secure from being 

 disturbed by so many creatures that prey on them, while they are under the ope- 

 ration of exchanging one state for another. From the 10th of May to the 1 5th 

 they are observal to be spread all over the country. As soon as the dew is ex- 

 haled, the cicadae are very active, flying about from tree to tree. The male 

 making a singing noise, calling the female, which he effects by a tremulous 

 motion he gives to two bladders, filled with air, under his wings. From their 

 nnmbers the noise is so loud and troublesome, that it interrupts conversation 

 with a continual din, from morning to evening. They continue coupling to the 

 l6th of May: soon after, the males disappear, and the females lay their eggs. 

 They are much larger than the males. They never could be perceived eating 

 any thing; yet as they are furnished with a long proboscis, which they frequently 

 extend, they may suck the dews, or the farina of flowers. The male, in coupling, 

 has at the end of his tail two hooks, with which he enters between the rings that 

 surround the body of the female. These, spreading internally, confine them 

 long together; which may be requisite, as there is a great number of eggs 

 to impregnate, some say 6 or 7 hundred. Soon after this work is over the fe- 

 male begins laying her eggs. To assist her in this operation, she is armed with 

 a dart near half an inch long, fixed between her breast and belly, and which 

 extends to the end of her tail. This she sheaths up, when it is not in use: with 

 this dart she pierces the small twigs of trees, and at the same time injects an egg. 



It is surprizing to see how quick they penetrate into hard wood, and croud it 

 full of eggs, the length of 2 or 3 inches, ranged in a line close together, from 

 12 to 18 in each partition. How she deposits the eggs in this direction it was 

 difficult to discover, they are so very shy while about this work : but John Bar- 

 tram, observing her, in the beginnmg of this operation, took a strong woody 



