HEMIPTERA. 627 



they hatch, and produce the Apple-tree-blight. The wounds of 

 this insect produce warts and excrescences on the surface of the 

 trees, and finally result in its death. 



The JUMPING PLANT-LICE, Psyllidce, (Psylla, Gr. Ps-dlla, a 

 gnat,) are similar to the Plant-lice, but more active. These are 

 dimerous; they have ten articulated antennae, and the females 

 have an ovipositor. 



The LANTERN-FLIES, Fulgorida, (Fulgora* Lat. from fulgeo, 

 to shine,) include a' number of trimerouu species of bright colors 

 and large size. Many of them have a curious prolongation of 

 the forehead, sometimes nearly as large as the rest of the body. 

 Whether they are luminous or not. is a point not positively set- 

 tled. They probably give out light at particular seasons. The 

 species F. candelaria, (Lat. from candela, a candle,) is yellow, and 

 the elytra black, marked with yellow spots. It is said a Chinese 

 edict exists against young ladies keeping Lantern-flies. 



The HARVEST-FLIES, Cicadida, (Cicada,) are distinguished by 

 their robust body, their large and triangular head, with three 

 stemmata, their prominent eyes; the antennae short and thin, 

 with six articulations, and, usually, by large transparent wings. 

 The Harvest-flies are trimerous. They have long been partic- 

 ularly noticed on account of the noise made by the male, differ- 

 ing in different species. The species which has attracted most 

 attention, is C. septendecim, (Lat. seventeen,) the SEVENTEEN 

 TEARS LOCUST, which often does very great damage to trees. 

 The female, with her ovipositor, inserts her eggs in their tender 

 branches, which causes them to die, so that the tops of the forests, 

 sometimes, on this account, look as if they had been scorched by 

 fire. Miss M. A. Morris has ascertained that trees also suffer 

 much from the larva of these locusts, which penetrate six inches 

 under ground, and reach the roots. She says further, that the 

 larvse are destroyed by those miners, the Moles. , 



The DOG-DAY HARVEST-FLY, C. canicularis, (Lat. from canicula, 

 the dog-star,) according to the observation of Mr. Harris, has, 

 for many years in succession, been regularly heard at Cam- 

 bridge, on the twenty-fifth day of July, between the hours of ten 

 in the forenoon and two in the afternoon. Its body is thicker 

 and proportionably shorter than that of the Seventeen Years 

 Locust, but its habits are quite similar. 



The HETEROPTERA, which have the upper wings partly thick, 

 and partly thin, include several families. Among these are the 



Notonectida, (Gr. back-swimmers,) the TRUE WATER-BUGS, 

 (Hydrocorisa,) named from their habit of swimming with the 

 back befcw. These, from the peculiar appearance of the body, 



