CHAPTER XIII. 

 Order PHYSOPODA (Phy-sop'o-da). 



Tlirips. 



The members of this order have four wings ; these are 

 similar in form, long, narrow, membranous, not folded, with 

 but few or no veins, and only rarely with cross veins ; they 

 are fringed with long hairs, and are laid horizontally along 

 the back when at rest. The metamorphosis is incomplete. The 

 mouth-parts are probably used chiefly for sucking; they are 

 intermediate in form between those of the sucking and those of 

 the biting insects {Fig. 138); the mandibles are bristle-like; 

 the maxillce are triangular, flat, and furnished zvitJi palpi ; 

 and the labial palpi are also present. The tarsi are two- 

 jointed, bladder-like at tip, and witlwut claws. 



Pull to pieces a clover-blossom or a daisy, and you will 

 probably find at the base of the florets many wee, black, 

 red, or yellowish insects. These are so small that it would 

 take a dozen or more placed end to end to measure an inch ; 

 and when disturbed they are apt to thrust the end of their 

 bodies up in the air as if they meant to sting, looking as 

 ferocious as such small insects can look. They are extremely 

 lively, leaping or taking flight with great agility. Under a 

 microscope their four narrow wings, delicately fringed all 

 around with long hairs, may be seen ; these wings are laid 

 flat down the back when at rest. The red ones are wingless, 

 and are the young of the black species. Some species eat 

 other insects, but most of them live upon vegetation. There 

 is one species, Limotlirips poaphagus (Lim'o-thrips po-aph'a- 



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