272 NATURAL HISTORY OF AQUATIC INSECTS 



its sheath. Lastly, the larvae of Hemerobius and 

 Chrysopa (Neuroptera) cover their bodies with the 

 skins of Aphides. 



It must not be supposed that little or no progress 

 has been made in the investigation of the Natural 

 History of the Trichoptera since the last centur}'. 

 Much excellent work has been done of late year.s, 

 especially by Pictet,^ McLachlan,'^ Fritz Miiller,^ 

 Klapalek,* and Morton/'* We have now fair accounts 

 of the structure and mode of life of many species ; 

 the indispensable work of classification, which was 

 hardly even attempted by Reaumur, has made satis- 

 factory progress, and the special student is thereby 

 spared much confusion and loss of time. Unfortu- 

 nately it is hardly possible to give to a beginner any 

 intelligible account of this valuable mass of detailed 

 work. Those young naturalists who seek for work more 

 promising than records of parish distribution would 

 do well to master and extend the results achieved by 

 the writers named. Such work will bring them into 

 actual contact with the problems of nature. 



1 Rech. pour servir a rHistoire et VAnatomie des Phrygan- 

 ides (1834). 



2 Monograph of British Caddis-flies (1865) ; Revision and 

 Synopsis of the Tridioptera of the European Faufia (1874-80). 



^ Zeits. f 7mss. Zoo/., XXXV. (1881) ; Zoot. Anz., 1879; 

 Ent. Soc. Trans., 1870. 



■* Arch, der Naturw. Landesd. von Boh?nen, VI. 5 ; VIII. 6. 

 (1888-93). 



^ Ent. Month. Mag. 1882. 



