ORDER II. The HEMIPTERA, have four wings, the two superior ones being semicrustaceous, and incurvent, i. e. the interior edges lie above one another.—This order includes 14 genera, viz. Blatta, Pneumora, Mantis, Gryllus, Fulgora, Cicada, Notonecta, Nepa, Cimex, Macrocephalus, Aphid, Chermes, Coccus, Thrips.