76 Journal of Entomology and Zoology 
SUMMARY 
1. Trithyreus has no sense organs but sensory hairs, so far as 
could be determined. 
2. The central nervous system resembles that of a spider quite 
closely, but the thoracic ganglion is more elongate and there is an 
abdominal ganglion. 
3. The brain is complicated, but few long tracts of fibers are 
evident. 
4. There may be areas which may represent anterior and poste- 
rior pairs of globuli of spiders and scorpions, but if so they do not 
have the same structure. 
5. There are no trachea in the central nervous system. 
6. The cells are uniform except for a mass each side of the 
brain in a cephalic dorsal position. 
7. This dorso-lateral group of cells strongly suggests a special 
higher center. Longer fibers were seen in connection with it than 
with any other part. 
REFERENCES 
Borner, C. 1904 
Beitrage zur Morphologie der Arthropoden. Zoologica. Heft 42. 
Cook, O. F. 1899 
“Hubbardia”: A new genus of Pedipalpi. Proc. Wash. Ent. Soc. 
Vol. IV. 
Haller, B. 1912 
Uber das Zentralnervensystem des Skorpions und der Spinnen. 
Archiv f. Mic. Anat. Bd, 79. Abt. I. 
(Contribution from the Zoological Laboratory of Pomona College) 
