1 84 ARTHROPOD A 



ture above the ventriculus and intestine made up of two sets of tubes 

 bound together into a compact mass. Two delicate oviducts pass 

 posteriorly around the ileum and colon to the ventral portion of the 

 body where they unite to form the single median vagina which opens 

 on the upper surface of the subgenital plate at the ovipositor. The 

 spermatheca is a small white pouch situated above the posterior end 

 of the vagina and communicating with it at the bursa copulatrix 

 by means of a minute orifice. The testes consist of two sets of 

 coiled tubules bound together in one mass and situated above the 

 intestine. Each testis sends off a vas deferens, the two uniting to 

 form a median ejaculatory duct. To each vas deferens is attached a 

 seminal vesicle, while cement glands empty into the ejaculatory duct. 



The Nervous System consists of dorsally situated cerebral ganglia, 

 two circum-esophageal connectives, a pair o{ fused sub-esophageal, 

 three pairs of fused thoracic, and five pairs of fused abdoyninal 

 ganglia. The thoracic ganglia are much larger than those of the 

 abdomen. Such highly developed concentration of ganglia in 

 cephalic and thoracic regions indicates a very high development of 

 reactions. In the ants and bees we find even greater concentration. 



Order 11. Hemiptera. — The Hejniptera have sucking mouth 

 parts and when wings are present, they have four. Most of the 

 Hemiptera are winged. Some generations of aphids are wingless. 



The Heteroptera, true bugs, include aquatic and land forms. 

 The giant water bugs (Belostomatidae) are important enemies of 

 insects, tadpoles and small fishes. The harlequin cabbage bug is an 

 important pest in the South, while the gj-een soldier bug and the 

 spined soldier bug are predaceous, destroying the larvae of injurious 

 Hexapoda. The squash bugs {Coreidae) and allied forms attack 

 squashes, pumpkins and other garden vegetables. The assassin 

 bugs {Reduviidae) are predaceous forms attacking other insects 

 such as the bed-bug. They may even attack man. The Indian 

 bed-bug {Cimex hemipterus) and the common bed-bug {Cimex lec- 

 tularius) transmit dum-dum fever, a flagellate disease. (See p. 29.) 

 The chinch-bug is one of the worst pests of corn known and also 

 attacks wheat. The leaf bugs attack foliage. 



The most important of the Homoptera are the scale insects and 

 the plant lice. The cicadas {Cicadidae) include a form known as the 

 seventeen-year " locust," which lives underground as a nymph from 

 thirteen to seventeen years. The eggs are laid in living twigs. 

 They hatch in about six weeks, burrow into the ground and feed on 



