Order THYSANOPTERA. 



The insects of this order are commonly known as "Thrips" and often 

 cause severe injury to growing plants. They are very small, very slender, 

 somewhat fusiform, with very delicate narrow fringed wings, which are 

 laid flat upon the back when at rest and are not even visible to the ordi- 

 nary observer without a lens. 



The mouth parts are made up of a number of slender lancets, only the 

 points of which protrude beyond the mouth opening. With these they 

 scrape the surface of the leaf or plant and exhaust the cell beneath, 

 leaving a yellow or whitish spot. Onion leaves sometimes turn almost 

 white under a severe attack, and "silver-tip" in grasses is often due to these 

 insects. Cabbage leaves are sometimes completely devitalized, and grow- 

 ing tips of young trees may be crippled. Not all species are harmful, 

 however, some of them occurring under such conditions as to make it 

 almost certain that they are predatory. Yet as a whole this little order 

 must be considered as injurious. 



As to remedial measures it 

 is difficult to make recom- 

 mendations. Ordinarily the 

 species flourish only in dry 

 weather, and their injuries in- 

 crease and manifest them- 

 selves in a dry season, or 

 after a protracted drought. 

 A cold rain may check them 

 when they threaten most, and 



d 



Fig. 28. Thrips tabaci: a, adult; b, antenna of 



same; c, young larva; d, full-grown larva; 



enlarged. 



a spray of cold water, thor- 

 oughly applied, is often suffi- 

 cient for their control. Tobacco decoction and soap suds are good addi- 

 tions, and may generally be relied upon to kill off the species in the green- 

 house and garden. 



Very little has been added to our knowledge of the New Jersey species 

 since the previous edition, and the number of forms has not been in- 

 creased by collections. Mr. Pergande is, therefore, still to be credited 

 with the notes. 



Family THRIPIDJE. 



COLEOTHRIPS Halid. 

 C. trifasciata Fitch. Infests grain and grasses. 



CHIROTHRIPS Halid. 

 C. antennatus Osb. Infests grasses. 



(8 3 ) 



