329} LARVAE OF THE TENTHREDINOIDEA—YUASA 11 



Still, our knowledge of the immature stages of the Tenthredinoidea is 

 very meager in comparison to that of the adult. The larvae of only 

 418 species out of the total of 2701 species listed by Konow in his mono- 

 graph (1905) were dealt with in his artificial table for the larvae. This was 

 less than sixteen per cent of the described species of the world up to his 

 time, and many larvae included in this sixteen per cent were known to 

 this authority only thru literature. According to Dyar (1895) less than 

 twenty-five per cent of the North American species have been recognized 

 in the larval state. It is no exaggeration to say that the larvae of more 

 than eighty per cent of the Nearctic species are yet to be described. 



Our knowledge of the physiology and morphology of the immature 

 stages of the Tenthredinoidea is exceedingly meager. The following list 

 includes most of the important literature: Graber (1890) on the embry- 

 ology of Arge berberides; Doncaster (1907) on the gametogenesis and 

 fertilization in Nematus ribesi; Biichner (1918) on the accessory chromo- 

 somes in Tenthredo, Allantus, Arge, etc.; Frenzel (1885) on the epithelial 

 regeneration of the alimentary canal of the larva of Cimbex; Holtz (1909) 

 on the histology and physiology of the digestive cells in the larva of 

 Nematus; Poletajew (1885) on the silk-glands of the larvae of Cimbex 

 and Tenthredo; Cholodkovsky (1897) on the blood and reflex bleeding of 

 the larva of Cimbex; and MacGillivray (1913) on the general external 

 anatomy of the larvae. 



The biology of the Tenthredinoidea abounds in phenomena of great 

 interest to experimental evolutionists and presents many problems of eco- 

 logical importance. The list of papers dealing with the life-history and 

 habits, especially of economic species, is fairly extensive. Cameron 

 (1882) has published an excellent summary of general biological and 

 ecological observations. The biology of the Nearctic Tenthredinoidea 

 has been discussed in detail by MacGillivray (1913). Since the biological 

 and ecological studies of the Tenthredinoidea are beyond the scope of the 

 present paper, readers are referred to the last-mentioned publication. 



Materials. — Four collections, designated for convenience as the Cor- 

 nell, Maine, MacGillivray, and Yuasa collections, contain most of the 

 materials used in this study. The writer has examined more than 2500 

 alcoholic specimens of larvae representing at least 400 species during 

 the course of this study. He has also, during the last few years, at Ithaca, 

 N. Y., and at Urbana, 111., made observations on the life-history and 

 habits of numerous species in his attempts to breed more than two hundred 

 and fifty species. 



The Cornell collection consists of about forty species and belongs to 

 the Cornell University. Most of the specimens were collected by Dr. 

 MacGillivray and Mr. Chester Young in the vicinity of Ithaca, N. Y. 

 They were in rather a poor state of preservation and proved useful only 



