Economic entomology for the farmer and fruit-grower : and for use as a text-book in agricultural schools and colleges . s in which the metamorphosis is incomplete ; but thereis an exception in the males of certain bark-lice, where there is areal, quiescent pupal stage. Before going further on this subject it is necessary to refer tothe peculiar little species known as Thrips, and belonging to thefamily Thripidce. They are now as a rule, and properly, sepa-rated from the true Hemiptera under the ordinal terms Thysan-optera, meaning fringe-winged, or Physopoda, meaning bladder-footed. They are a
Economic entomology for the farmer and fruit-grower : and for use as a text-book in agricultural schools and colleges . s in which the metamorphosis is incomplete ; but thereis an exception in the males of certain bark-lice, where there is areal, quiescent pupal stage. Before going further on this subject it is necessary to refer tothe peculiar little species known as Thrips, and belonging to thefamily Thripidce. They are now as a rule, and properly, sepa-rated from the true Hemiptera under the ordinal terms Thysan-optera, meaning fringe-winged, or Physopoda, meaning bladder-footed. They are always small in size, slender, active, with thehead so narrow that they seem pointed at both ends. The wingsare laid longitudinally on the back, and are very narrow, trans-parent, without veins or with mere rudiments, but with lengthyfringes, which give them a characteristic and i)eculiar feet are not terminated by pointed claws as usual, but bysmall, bladder-like dilations of the terminal joints. They runand fly readily, and some of them jump much as do spring-tails. AN ECONOMIC ENTOMOLOGY. Fig. The mouth structure is in some respects intermediate betweenthat of the true bugs, as already described, and that of the man- dibulate type ; but there are notrue mandibles, and the insects can-not chew their food, hence comenaturally, for our purpose, into thisorder. The species of Thrips are oftenseriously injurious to sometimes attack onions ingreat numbers, puncturing the suc-culent leaves, and everywhere leav-ing a small yellow dot. As theseincrease in number the leaf losesvitality, the top itself turns yellow,and in serious cases the rich green Thrips tritici.—b, antenna ; c, a tarsus, of a normal OnioU field is changed to a peculiar, sickly yellow. Theinsect is yellowish when immature, and blackish-brown when thewings are developed. Cabbages sometimes suffer in a similar manner. The insectsin this case are yellow, and congregate in large numb
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectinsectp, bookyear1906
