526 A CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



sanopterorum (1949) telescopes much of this unnecessary superstructure. Hood 

 in 1915 estimated that about 25,000 forms would be found to exist; to date 

 hardly half that number have been described. 



In the modern sense the old carded specimens are impossible to work with 

 or to identify to species. Carefully prepared slide mounts are a necessity and 

 descriptions and drawings prepared from them should be done with the best 

 optical equipment. At present the greatest need for the younger workers is up- 

 to-date illustrated keys to the species. 



Geographically, our knowledge of the group is most complete in Europe and 

 in North America. Hood and Moulton have greatly broadened the knowledge 

 of the South America fauna. Priesner has done the same for North Africa, 

 Faure and others in South Africa, Ayyar in India, Kurosawa, Karny, and Pries- 

 ner in other parts of Asia, Bagnall and Moulton in Australia. In China, equa- 

 torial Africa, India, Micronesia, and South America there remain many species 

 yet to be collected and described. 



The economic importance of thrips was recognized almost as early as their 

 taxonomic independence. The scarring and blasting of fruits, vegetables, and 

 flowers were described in early gardening guides in Europe about one hundred 

 and fifty years ago. In North America, Fitch (1855) and later Osborn, Per- 

 gande, Ashmead, and others described injurious forms, particularly in Insect 

 Life. We now know that some species are predaceous, while others are fungus- 

 feeders, gall-formers, and vectors of plant disease (Sakimura, Bagnall, Karny, 

 Hood, etc.). 



Our knowledge of the morphology and internal anatomy of thrips has been 

 advanced by the classic studies of Jordan, Klocke, Peterson, Borden, Doeksen, 

 Reyne, Sharga, and Pussard-Radulesco. Extensive studies of the immature forms 

 have been published by Priesner, Karny, Reyne, Melis, and Speyer. Kurdjumov 

 first observed the cocoon-spinning capacity in this transitional order. 



The thrips collections of note are the very extensive private collections of H. 

 Priesner, which includes Karny's, and that of J. D. Hood. Museum collections are 

 those of the British Museum, including the Bagnall Collection, U. S. National 

 Museum, California Academy of Sciences (Moulton collection), Canadian Na- 

 tional Museum, and Queensland Museum. University and other institutional 

 collections are those at the Illinois Natural History Survey, University of Florida 

 (Watson collection). University of Massachusetts (Hinds collection), and the 

 University of California. Private collections containing much valuable material 

 are those of Faure, Jacot-Guillarmod, and Hartwig of South Africa; those of 

 Williams, Morison, Speyer, Doeksen, Pelikan, and the late Hukkinen, in Europe; 

 those of Sakimura, Bianchi, Kurosawa, and Takahashi in the Orient (little is 

 known of collections in India); and those of Andre, Steinweden, J. G. Watts, 

 H. E. Cott, and R. L. Post in the United States. 



In the future, to bring the order Thysanoptera up to the status of other 

 more completely studied insect groups, it will be necessary for two types of work 

 to continue: the collection and adequate description of new forms and the peri- 

 odic compilation and evaluation of the accumulated knowledge. In this process 

 the concept of the relative value of family, generic, and specific characters should 

 be refined and better stabilized. 



