lOOLOGlCAL lABORAIORY, McGRAW HAU 



THE TET8AN0PTEBA. 121 



Order 7. Thysanoptera. — Thrips and its allies were re- 

 ferred by Haliday to a distinct order. The mouth-parts 

 form a sort of beak ; the mandibles are bristle- 

 like ; the maxillje flat, triangular, bearing two- to 

 three-jointed palpi ; the labial palpi are very 

 short, two- to three-jointed. The wings are small, 

 long and narrow, fringed; both pairs of equal 

 size, usually without veins. The antenna3 are 

 five- to nine-jointed. 



Order 8. llemiptera. — The bugs (Fig. 150) have 

 a long beak bent on the breast. They suck the 

 juices of plants and blood of insects. The chinch- 

 bug (Fig. 151) is fearfully destructive in 

 certain years to corn and wheat ; collecting 

 under the base of the leaves in great num- 

 bers, it sucks the sap and kills the plant. 



While most insects live but one and some 

 live two years, the seventeen-year Cicada 

 (Fig. 152) lives over sixteen years as a larva, 

 becoming a pupa and finally acquiring 

 wings in the seventeenth year. Sq'uSh-bugr Natural 



The Aphis or plant-louse (Fig. 153) is'*'^'='- 

 provided with two tubes on the end of the body from which 



n 



Thrips. 



FiQ. 151.— Chinch-bug. a, 6, eggs; c, e, larva; /, g, pupa; i, beak. 



''honey dew" drops, which attracts ants, wasps, etc. In 

 summer the female plant-lice bring forth young alive, and 

 as there may be nine or ten generations, one virgin Aphis 



