Vol. XXVIII, pp. 53-60 March 12, 1915 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



AN OUTLINE OF THE SUBFAMILIES AND HIGHER 

 GROUPS OF THE INSECT ORDER THYSANOPTERA. 



BY J. DOUGLAS HOOD, 



United States Biological Survey. 



Not many years ago the order Thysanoptera, when recognized 

 at all, was known as a small group of unimportant insects. In 

 1907 only about 45 genera and 175 species had been recorded in 

 the scientific literature of the entire world. During the last 

 seven years, however, the activity of specialists has increased 

 the number of known genera to 169 and the known species to 

 795. Economically, too, the group has come into greater 

 prominence, and the Orange Thrips, Pear Thrips, and Tobacco 

 Thrips have taken a place among the important pests of their 

 respective food plants. The systematic and biological work 

 have each proved a stimulus to the other, and some knowledge 

 of these tiny insects has become necessary to every working 

 entomologist. 



With the increase in the size and importance of the group 

 has come the necessity for a more comprehensive classification 

 than that of Uzel, proposed in 1895. Mr. Richard S. Bagnall, 

 in a recent paper (Bagnall, 1912b) has suggested the division 

 of the order into three suborders, one of which he calls 

 Poly stigmata, in agreement with an opinion which had been 

 expressed by the writer (Hood, 1912). These suborders he 

 further divides into the nine families Urothripidas, Phloeothrip- 

 idse, Ecacanthothripidie, Idolothripidso, iEolothripidtE, Heter- 

 othripidae, Pancha^tothripidse, Ceratothripida:\ and Thripidse. 

 Shortly after this Dr. Filip Trybom, in a paper on some 

 Thysanoptera from Natal and the Zululand (Trybom, 1912), 

 7— Proc. Biol. Soc. Wash.. Vol. XXVIII. 1915. (53) 



