ANNULOSA: INSECTA. 



349 



inner margins of the wings are straight or contiguous. 

 The antennae are moderate in size, and composed of a 

 few large joints. They are divided into the two groups 

 of the Hydrocoriscz (Water-bugs) and Geocorisce (Land- 

 bugs), according as they are aquatic or mainly terrestrial 

 in their habits. 



Amongst well-known members of this group may be men- 

 tioned the Forest-bugs and Field- 

 bugs (Pentatoma, and its allies), the 

 Bed-bug (Cimex lectularius), the 

 Boat-fly (Notonectd), the Water-scor- 

 pions (Ntpa, fig. 182, B), and the 

 Water-spiders (Hydrometrd). 

 Sub - order c. Thysanoptera. 

 Mouth with mandibles and 

 maxillae, furnished with palpi. 

 The wings with few or no ner- 

 vures, fringed. In this sub- 

 order are only the little insects 

 which form the genus Thrips 

 (fig. 182, A), and some allied 

 forms. They live upon plants, 

 and differ from the typical 

 Hemiptera both in the struc- 

 ture of the wings, and in the 

 fact that the beak-like rostrum 

 really contains palpate mandi- 

 bles and maxillae. 

 ORDER VI. ORTHOPTERA. 

 Mouth masticatory ; wings four, 

 sometimes wanting ; the anterior pair 

 mostly smaller than the posterior, 

 semi - coriaceous or leathery, usually 

 with numerous nervures, the inter- 

 spaces between which are filled with 

 many transverse reticulations; sometimes overlapping hori- 

 zontally (Cockroach), sometimes meeting like the roof of a 

 house (Grasshoppers). Posterior wings usually having their 

 front portion of a different texture from their hinder portion, this 

 latter being almost always more transparent, and when not 

 in use folded longitudinally like a fan. Posterior wings often 

 wanting in the females of the Blattida. Antennae usually 

 filiform. Metamorphosis semi - incomplete (sometimes, how- 

 ever, the adult is apterous, when it becomes almost impossible 

 to distinguish the larva, pupa, and imago). 





Fig. 183. Orthoptera. The com- 

 mon Cockroach (Blatta orienta- 

 lis), male and female. 



