Concerning the insects, many extensive works have been published 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 definite 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, ’80, and in more recent times we have the valuable works of Kenyon, ’96, 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.