CONTRIBUTION TO A MONOGRAPH OF THE INSECTS OF 

 THE ORDER THYSANOPTERA INHABITING NORTH 

 AMERICA. 



By Warren Elmer Hinds, 



Of the Massachusetts Agricultural College. 



INTRODUCTION. 



Very little attention has been given to the Thysanoptera of North 

 America. So far as I can learn, descriptions or names of only twenty- 

 three species have thus far (June, 1902) been published, besides three 

 which have been recognized as previously descril)ed from Europe. 

 Of the twenty-six species thus known in this country, four at least are 

 certainly unrecognizable (Z;;y.r>^^y^>s' ^f/vY/c/ Packard, rhla'othrips mali 

 Fitch, P. caryai Fitch, 7y//v> phylloxera Riley). Of the remaining 

 twenty-two, six have been found identical with previously described 

 species and therefore become synonyms— the large number is not 

 surprising as many of the early descriptions are entirelv too brief to 

 insure positive identification. Therefore only sixteen "species have 

 hitherto been known to occur in this country. We may say that 

 almost no systematic work has been done on the order ii/the United 

 States, and, with the exception of a study of the '^Thripidse of Iowa," 

 by Miss Alice M. Beach, most of the descriptions are scattered 

 through different publications. I have endeavored to collect and 

 present here such important facts as have already been published 

 relating to members of this order, together with' the observations 

 which I have been able to make. An attempt has ])een made to place 

 the work upon a systematic basis, and in order to make the descrip- 

 tions uniform, and thus comparative, all the existing types that it has 

 been possible for me to see have been examined and redescribed. In 

 all, thirty-seven species are thus treated in the systematic part of this 

 paper. Other descriptions which it has not been possible for me to 

 place are given together by themselves in the hope that some one 

 more fortunate or skillful than myself may have material by which 

 to identify them. 



Proceedings U. S. National Museum, Vol. XXVI— No. 1310. 



79 



