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Authors have hitherto always considered this remarkable family as vegetable-feed- 

 ing, but from many facts which I have observed, one of which I have recorded (Proc. 

 Eut. Soc. Phila. , I, p. 310). I believe that they are generally, if not universally, 

 insectivorous, and that those that occur on the ears of wheat, both in the United 

 States and in Europe, are preying there upon the eggs or the larvae of the Wheat 

 Midge (Cec. tritici), and are consequently not the foes, as has been generally imagined, 

 but the friends of the farmer. In confirmation of these views, it may be remarked 

 that the very same species {Thrips cerealium), which has been stated by all European 

 authors to attack the ears of the wheat, was found by Vasali Eandi in Italy *'to gnaw 

 the stems of the wheat above the knots and cause the abortion of the ear." (See 

 Westw., Intr., II, p. 4.) Is it probable that the same species should attack the same 

 plant in two such very different parts ? I believe that the Italian Thrips were attack- 

 ing Hessian Flies (Cec. destructor) or some such wheat-destroying insects that inhabit 

 ■** the stem above the knots," and that it was these last and not the Thrips that caused 

 the "abortion of the ear." The Thrips that were supposed to do so much damage in 

 Wisconsin, as related by Dr. Fitch (N. Y. Kep., I, p. 304), were said to attack both 

 the blossoms of the wheat and the blossoms of the clover. But it is not the genera- 

 habit of insects to prey at the same time upon two plants which are so widely dis. 

 tinct as wheat and clover — the one Monocotyledonous, the other Dicotyledonousl 

 Even the Polyphagous army worm refuses to eat clover. 



Now, as already stated, I have myself noticed several Thrips in June both in 

 the larva and imago state on the Cecidomyidous gall S. cenigma, and have raised the 

 larva to maturity in a breeding-jar in which there was nothing but that gall. More- 

 over, Dr. Fitch found his Plxlwotlirips caryce in hickory galls, which are manifestly 

 either closely allied to or identical with the Cecidomyidous hickory gall Tubicola O. 

 S., though he doubts whether these galls were produced by the Thrips or by some other 

 ^usect (N. Y. Rep. II, p. 127), and Osten Sacken observes of the galls of the Cecido- 

 myidous Lasioptera vitis O. S. that some of the galls' hollows are often abandoned 

 by their inmates and invaded by numerous Thrips. (Dipt. N. A., p. 201.) 



lu Practical Entomologist, Vol. I, p. 21, he says : 



I do not believe that the Thrips of entomologists are, as has hitherto been uni- 

 versallj^ believed, vegetable feeders ; but that, on the contrary, they are cannibal 

 insects, preying upon injurious larvae, and therefore the friends and not (he foes of 

 the agriculturist. 



"to' 



Still further in the Practical Entomologist, Vol. II, p. 50: 



Naturalists hitherto had always supposed that these Thrips were vegetable 

 feeders and injurious to plants. In the Proceedings (Entom. Soc. Phil., Ill, pp. 611, 

 612) I suggested " that they are generally, if not universally, insectivorous, and that 

 those that occur on the ears of the wheat, both in the United States and in Europe, 

 are j)reying there upon the eggs or larvae of the Wheat Midge {Di2)losis tritici), and 

 are consequently not the foes, as has been generally imagined, but the friends of the 

 farmer. " At the conclusion of this passage I gave several reasons for my belief, and 

 I have since found Thrips i)reying upon the gall-making larva' of more than twenty 

 different galls, growing on different trees and other plants, so that there is now no 

 manner of doubt in my mind that Thrips is a true cannibal insect. The imi)ortance 

 of this discovery may be seen at once. The larva" of a minute Flea-beetle (Haliica) 

 often grieviously infests clover blossoms, feeding upon and destroying a large portion 

 of the seed. A Thrips occurs also sometimes in large numbers on these blossoms. 



Hitherto fanners, when they detected Thrips on their clover, had supposed that a 

 new enemy was invading it. Now, when they see the Tlirips there, they may go to 

 bed and sleep comfortably, satisfied that the depredations of the real enemy are about 

 to be checked; and in the same way, whenever in wheat fields infested by the larvae 

 of the Wheat Midge (popularly known in the East as the "Milk Weevil" and in the 

 West as the "Red Weevil "") Thrips are discovered in the ears of the infested grain, 



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