ROSS: TRICHOPTERA 539 



The modern pattern of caddis-fly study was initiated suddenly and deci- 

 sively by the English worker, Robert IMcLachlan, in his monumental treatise 

 on the European caddis-fly fauna (1874-1884). McLachlan defined most of the 

 modern families and genera, introduced genitalic structures as the chief basis 

 of specific diagnosis, and gave a comprehensive set of clear descriptions and 

 illustrations for most of the European species and many of the Asiatic ones 

 as well. 



McLachlan's work served as a stimulus to a group of energetic students of 

 the order who described species from every part of the globe. Nathan Banks 

 (1892 to 1951) was especially active in investigating North American, South 

 American, and Pacific Island forms; A. B. Martynov (1892-1934) described 

 much of the Asiatic and Oriental fauna, with especially valuable papers on the 

 Siberian forms; George Ulmer (1900 to date) not only studied the Oriental, 

 Neotropical, and African faunas but also wrote the Trichoptera volume (1907) 

 of Genera hisectorum, which has been and still is the starting point of all seri- 

 ous world studies in the order; Longinos Navas (1905-1933), probably the most 

 prolific writer, described material from all areas; and Martin E. Mosely (1919- 

 1948), whose many papers are ably and fully illustrated by D. E. Kimmins, 

 elucidated the Trichoptera of many lands. 



Soon after the turn of the century the tremendous upsurge of interest in 

 limnological work added its impetus to caddis-fly studies, especially in the inves- 

 tigations of immature stages. In this field outstanding contributions were made 

 in Europe by Thieneman (1903-1926), Siltala (1900-1908), Wesenberg-Lund 

 (1908-1915), and Ulmer, whose Trichoptera volume (1909) of Brauer's Suss- 

 wasserfauna DeutscMands was of great value for diagnosis. In North America 

 similar studies were reported by Vorhies (1905-1913), Lloyd (1915-1921), and 

 Krafka (1915-1926). 



A great boon to taxonomic work on the adults was the discovery late in the 

 last century of the clearing or eviscerating action of sodium and potassium 

 hydroxide solutions. This treatment is especially effective in studying the geni- 

 talic structures of insects. One of the first champions of this procedure in Tri- 

 choptera studies was Cornelius Betten (1901 to date). Dr. Betten not only 

 instructed many students in the techniques of trichopterology, but gave North 

 America its finest reference book on the order, his TricJwptera of New York State, 

 published in 1934 as Bulletin 292 of the New York State Museum. 



Many other workers have been attracted to the order in the last few decades, 

 and these have added the results of their work to the total. In North America 

 the more active have been Tj. J. Milne, D. Ch Denning, and the author. In 

 Europe D. E. Kimmins, F. Schmid, and F. C. IT. Fischer are especially active 

 in the group. 



Looking over the record, we see that our knowledge of the world fauna has 

 increased from the dozen or so species described in Linnaeus' time to the four 

 or five thousand known today. Tlie list of the North American fauna has grown 

 from eight or nine in Say's time to eight or nine hundred descriljed today. Im- 

 mature stages are known for a surprising proportion of tlie genera (70 per cent 

 in North America). Integration of larval and adult cliaracters has aided tre- 

 mendously in clarifying concepts of classification. 



Trichoptera is a relatively easy order in which to start studies. There are 



