1NSECTA. 581: 



labium of four joints, and the labrum long, subulate, and 

 striated above. Among these the Pentatomadae have five- 

 jointed antennae, as Pentatoma, Cydnus, Tetyra, and Elia. 

 The Coreidae have only four joints in the antennae, as Co- 

 reus, Berytus, Lygaeus, Capsus, Miris, and Mydocha. In 

 another group, the labium consists of only three joints, 

 sheathing the labrum which is short. In the Reduviadae, 

 the rostrum is curved, as Reduvius and Plocaria ; while in 

 Cimicidae it is straight, as in Cimex, Tingis, Aradus, and 

 Phymata. In a third group the labium consists of two or 

 three joints, and does not embrace the labrum, as the Acan- 

 thidae, including the Acanthia and Galgulus. 



The aquatic heteroptera live in or upon the water. They 

 are destitute of ocelli. In the Hydrometridae, including 

 Hydrometra, Velia, and Gerris, the antennae are long, and 

 inserted between the eyes. In the remaining families, the 

 antennae are short, and inserted under the eyes, and are 

 shorter than the head. In the Nepadae, the tarsi of the 

 fore-legs are indistinct, as Naucoris, Nepa, and Ranatra. 

 In the Notonectadae, the anterior tarsi are distinct, as in 

 Notonecta, Plea, Sigara, and Corixa. 



II. HEMIPTERA HOMOI>TERA. In the insects of this di- 

 vision, the rostrum seems to originate from the chin. The 

 second segment of the thorax is as long as the first. There 

 are two or three ocelli. The Cicadiadae have three joints in 

 the tarsi, the antennae consist of six joints, and there are 

 thiee ocelli, as Cicada. The Fulgoradae have three tarsal 

 joints, and only three joints to the antennae, and two ocelli, 

 as Fulgora, Plata, Issus, Tettigometra, and Delphax. 

 The Cercopidae differ from the preceding in the antennae 

 being inserted between the eyes, as Cercopis, Etalion, Le- 

 dra, Membracis, and Tettigonia. The Aphisida? have two 

 joints in the tarsi, as Aphis, Psylla, Thrips, and Aleyrodes. 

 The Coccidae have only one tarsal joint, as Coccus. 



