Eleventh Report op the State Entomologist 247 



Remedies. 

 The injury inflicted by this minute insect when occurring in such 

 myriads can be prevented, if, at its first detection, the plants be 

 thoroughly sprayed with fresh pyrethrum in water, in the proportion of 

 one ounce to two gallons of water. See Insect Life vii, p. 392. A spray- 

 ing with kerosene emulsion would also be eftective. 



Some Characters of the Thripidse. 



The Thripidce, when full study shall be given them, will doubtless be 

 found to embrace numerous species. Those known to us as occurring in 

 the United States have been referred to ten genera, such as Thrips, 

 PhlcEothrips, Limothrips, etc. — the names of all terminating in thrips. 

 Their structure places them quite low in the class of insects. They have 

 been included by some authors (as Packard) in the order of Hemiptera. 

 They have also affinities with the Orthoptera and Neuroptera. They may 

 not properly be assigned to any of the old seven orders, and there is there- 

 fore a disposition to set them apart in a distinct order, with the name 

 Thysanoptera (meaning fringe-wings). Physopoda drawn from the bladder- 

 like termination of their feet, has also been proposed for them. They 

 are small, elongate creatures, measuring less than one-tenth (some less 

 than one-twentieth) of an inch in length, with narrow, long-fringed wings 

 lying flat on their backs in repose. They can run rapidly, often turning 

 up the tip of their abdomen after the manner of the rove-beetles, or they 

 leap or take wing when alarmed. The common ox-eye daisy, or a head 

 of red clover, plucked at almost any time, will give examples of these 

 interesting forms. 



A few years ago the ThripidtR were thought to be harmless insects, 

 nearly all of them possessing carnivorous habits, and living mainly on 

 other insects. More careful study has shown that many are herbivorous, 

 and may be quite injurious to the plants that they infest, their strangely 

 constructed mouth-parts being adapted to both biting and sucking. 



Some Literature of the Thripidse. 

 An excellent study of the food-habits of the family has been given by 

 Prof. Osborn in Instd Life, vol. i, 1888, pp 137-142, in which the food 

 of 26 species is given, consisting of apple, strawberry, olive tree, potato, 

 melon, onions, corn, clover, grasses, timothy, wheat, rye, hops, green- 

 house plants, and species of Compositce. See also the following publica- 

 tions for additional information regarding the family. 



Westwood : Introduct. Class. Insects, ii, 1840, pp. 1-5, fig. 57 (Thysanop- 

 tera, structure, habits, systematic position). 



