BRINCK: PLECOPTERA 513 



naean epigons produced scattered descriptions of stonefiies, but most of them are 

 poor and rarely allow identification without examination of the types. 



The beginning of our knowledge of North American stonefiies was made by 

 Thomas Say, who described four species in 1823 {Godman's Western Quarterly 

 Reporter, Vol. 2, no. 11). 



In the 1830's Edward Newman of England started detailed work on the 

 Plecoptera. But the first person to make a thorough study of the group was 

 the Swiss F. J. Pietet. In his Histoire naturelle generaJe et particuliere des in- 

 sectes Neuropteres, he devoted 423 pages and 53 plates to the Plecoptera. This 

 was an important work, presenting much information on the morphology, anat- 

 omy, biology, and taxonomy of these insects. Pietet also showed that the nymphs 

 are quite different from the larvae of the caddisfiies, contrary to the views of pre- 

 vious authors. The first description of the postembryonal development of a 

 perla, by de Murault in 1683 (Ephemerides Naturae Curiosorum) had been 

 forgotten. 



About 1853 approximately 150 species of stonefiies had been recognized^ 

 though not adequately described. There were many more names available but 

 the technique of studying these insects had advanced very little and many of the 

 descriptions could not be interpreted. Pinned specimens often shrink and change 

 color, so the superficial diagnoses of that time, giving color and rough external 

 structures, were not very useful. The general classification of the group was 

 still undeveloped. Most of the described species were central European. Scat- 

 tered descriptions of species from other parts of the world had appeared but 

 no definite zoogeographical views could be formed. 



This state of affairs continued throughout the nineteenth century. Several 

 authors described new species but few of the descriptions were adequate. No 

 clear conception existed with regard to the limits of the species. During this 

 time the first comprehensive review of the American fauna was given by H. A. 

 Hagen in his Synopsis of the Neuroptera of North America (1861). 



A sound basis of study developed when workers began to use genitalic char- 

 acters. A. Gerstacher in a paper on Plecopteran gills (1874) had attempted the 

 first description of the genitalia of a Nemoura sp. but it was not until the 1890's 

 that taxonomists began in earnest to clarify the subject by means of this method. 

 In 1894 K. J. Morton based a study of European nemouras on male genitalia. 

 Fr. Klapalek in 1896 wrote a fundamental paper on the genitalia of stonefiies. 

 P. Kempny dealt thus with the genus Leuctra in 1898, and in 1902 F. Ris pub- 

 lished a monograph on the central European nemouras, based on KOH prepa- 

 rations of the male and female abdomina. The investigations proved that in many 

 genera the male genitalia are very diverse and offer excellent specific characters. 



A classification of the stonefiies was practically nonexistent until Klapalek 

 in 1905 placed the Hungarian species in two suborders and six families, pri- 

 marily based on the structure of the palps and the cerci. In 1909 G. Enderlein 

 presented a more elaborate classification, based on all genera adequately de- 

 scribed at that time (40). He distinguished two suborders and five families, 

 dropping three of Klapalek's units. 



Klapalek wrote seventy papers on stonefiies. Several of these monographs 

 dealt with genera or families and are still of great value. It is a pity, however, 

 that he did not use KOH preparations or a similar method, instead of describ- 



