ANNALS 



OF 



The Entomological Society of America 



Volume IV SEPTEMBER, 1911 Number 3 



THE STRUCTURE OF THE CENTRAL NERVOUS SYSTEM 

 OF CORYDALIS LARVA. 



By William A. Hilton. 



Concerning the insects, many extensive works have been pub- 

 lished upon the nervous system from early times down to quite 

 recently. The work of Dujardin, '50, may be said to be a 

 starting point. Numerous papers by Villanes from '87 to '93 

 give general accounts of the structure, but nothing very def- 

 inite as to the distribution of individual nerve termination and 

 origin within the ganglia. The extensive work by Saint-Remy, 

 '90, is also a somewhat fragmentary account of numerous forms 

 of tracheate head ganglia. Other earlier papers dealing with 

 cephalic ganglia in particular are those of Newton, '79, and 

 Packard, 'SO, and in more recent times we have the valuable 

 works of Kenyon, '9G, and Haller, '04. In connection 

 with the structure and relationships of abdominal ganglia, the 

 investigations of Binet, '94, and Benedicenti, '95, should be 

 mentioned ; and for a summary of the form and structure of the 

 insect nervous system, the general work of Berlese, '97, is 

 invaluable. 



Although there are numerous and extensive papers dealing 

 with the structure of insects, very few give a very complete 

 account of the whole nervous system of a single species and 

 practically no single work treats of the larval centers in much 

 detail, although numerous papers take up the development and 

 some as Bauer, '04, consider the transformations of larval into 

 the adult conditions. 



The external anatomy and general distribution of ganglia 

 and nerves of Corydalis have been studied by Krauss, '84, and 

 by Hammar, '08. The relations of the trachea to the nervous 

 system and their distribution within it by Hilton, '09. The 



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