430 GENERAL ZOOLOGY 



flagellated Protozoa that are capable of rendering digestible 

 the cellulose of wood eaten by the termites. It has been 

 shown that without the flagellates termites are unable to digest 

 cellulose. The mouth parts are for chewing, and meta- 

 morphosis is gradual. Some tropical species build nests 10 or 

 12 ft. in height. In the United States they live in mines in the 

 earth and in wood. They cause considerable damage to the 

 wooden structure of buildings. 



Example: Reticulitermes flavipes, a common termite of North- 

 eastern United States. 



Order Hemiptera (Half- winged) . Bugs. The proximal halves 

 of the anterior pair of wings are thick and the extremities, 

 which overlap, are very thin. The posterior wings are mem- 

 branous. The mouth parts are for piercing and sucking. 

 Metamorphosis is incomplete. Many have stink glands 

 located on the abdomen. 



Examples: Anasa tristis, the squash bug; Lygaeus kalmii, the 

 milkweed bug; Lethocerus americanus, the giant water bug or 

 electric-light bug; Gerris remigis, the water strider; Cimex 

 ledularius, the bedbug; Blissus leucopterus, the chinch bug; 

 Arctocorixa alternata, the water boatman. 



Order Homoptera (Same-winged). Cicadas, aphids, and gall 

 insects. There are usually two pairs of wings of uniform 

 thickness. Some are wingless and in one family (Coccidae) 

 the posterior pair of wings is reduced to a pair of club-shaped 

 halteres. The mouth parts are for piercing and sucking. 

 Metamorphosis is incomplete. 



Examples: Tibicen linnei, the "dogday" cicada; Magicicada 

 septemdecim, the 17-year cicada, whose larval stage lasts 17 

 years; Aphis gossypi, the melon aphis, one of the plant lice; 

 Phylloxera vitifoliae, forms galls on grape leaves; Aspidiotus 

 perniciosus, the San Jose scale insect. 



Order Anoplura. Lice. These are wingless parasitic insects 

 whose mouth parts are in the form of a tubular proboscis 

 provided with sharp stylets. Recurved hooks in the base of the 

 proboscis serve to anchor the proboscis after it has been inserted 

 in the skin of the host. Metamorphosis is incomplete. 



Examples: Pediculus capitis, the head louse; Pediculus 

 corporis, the body louse or "cootie"; Phthirius pubis, the crab 

 louse. 



