PACKARD.! THE ONION-THRIPS. 743 



Ware, of Swami)SCOtt, to his serious loss of onions from the attacks of 

 a minute insect. The leaves were observed to suddenly turn yellow and 

 wilt, and the plant died. In this way large patches became infested and 

 turned yellow, until in two or three days these prolific insects spread 

 over the whole field. They seemed to increase most rapidly during the 

 unusual dry, hot weather that we experienced about the middle of last 

 August. On the 11th of August a whole acre was thus cut off. Mr. 

 Ware informed me that the onion-plants have been more or less infested 

 in this way for some fifteen years, but the damage done this year was 

 greater than ever before. This evil seems wide-spread in Essex County, 

 as not in Swampscott alone, but in Lynn, Salem, and parts of Danvers, 

 the onion-crop has been similarly infested. About $100,000 worth of 

 onions are raised in Essex Coun^^y alone, and Mr. Ware judged that at 

 least a tenth part was destroyed by this new pest ; so that in one county 

 alone and by one kind of injurious insect we have in one season lost 

 $10,000. The onion-crop is next to the hay-crop in value, as it is sold 

 for cash. 



*• Onexamining the specimens brought into the Museum of the Peabody 

 Academy of Science the leaves were found to be covered with hundreds 

 of a minute thrips, which, by gnawing the surface of the leaves, had 

 caused them to turn white in spots, and subsequently yellow ; where 

 they were most numerous the outer skin of the fleshy leaves was 

 entirely eaten off, and though it was difficult to imagine that so minute 

 insects could have caused the death of so stout and thick-leaved a plant, 

 yet here were hundreds of the culprits in all stages of growth plying 

 their jaws before our eyes in proof. 



"This insect, which occurred in both sexes and in all stages of growth 

 from larvae of minute size, proved to be the wheat-thrips of Fitch {Li7)i- 

 otlirips tritici), who gives an account of its appearance and habits in his 

 'Second Report on the Noxious, etc., Insects of New York,' p. 304. His 

 attention was first called to this insect by a correspondent in Wisconsin, 

 who found them in great numbers in blossoms of various plants. He 

 wrote Dr. Fitch that they first 'made their appearance about the middle 

 of June, or at least they were then first noticed, so far as I have heard. 

 For about two weeks they were found in the blossoms of wheat and of 

 clover, causing numbers of the blossoms to wither, and in some cases 

 the kernel was also attacked.' Dr. Fitch himself never seems to have 

 noticed this insect in New York, nor that it has ever been found in the 

 onion, but thinks it is the species to which Dr. Harris refers in his 

 ti^eatise. In that work the author speaks of a ' pernicious insect in the 

 ears of growing wheat,' which ' seems to agree with the accounts of the 

 Thrips cerealium which sometimes infests wheat in Europe to a great 

 extent.' From his brief description it is probably the insect now under 

 consideration to which Dr. Harris refers. 



"The various kinds of thrips are minute, narrow-bodied insects seldoui 

 exceeding a line in length, and remotely allied to the bed-bug and squash- 

 bug in structure, but differing from them in having free jaws adapted to 

 biting, while those of the bed or squash bug form with the other mouth- 

 organs a sharp, hard beak, with which they puncture leaves, or the flesh 

 of their victims, when carnivorous in their tastes. These thrips are 

 further distinguished by their wings being very long and narrow, and 

 beautifully fringed ; and when folded over their back they do not conceal 

 the body beneath, as is usually the case. Moreover, they are exceed- 

 ingly active in their habits, running or leaping like fleas. 



"Dcficrq)tion. — The females alone are winged, the males being wingless and closely re- 

 sembling the larvaj. Tlie body of the female is smooth and shining, uniformly green- 



