364 G. E. GATES. 



11. One or more pieces both anteriorly and posteriorly are very 

 frequently autotomized after operation by posterior portions. 

 Sometimes the whole tail portion fragments into pieces six to ten 

 millimeters in length. Anterior ends have not been observed to 

 autotomize. 



12. A fly A. scalaris Lw. has been bred from portions of P. 

 excavatus. Parasitism by this insect may possibly be responsible 

 for the mutilated specimens and for the autotomy following op- 

 eration. 



REFERENCES. 

 Beddard, F. E. 



'86 Description of Some New or Little-known Earthworms. P. Z. 



S., 1886, pp. 298-314. 

 Morgan, T. H. 



'95 A Study of Metamerism. Q. J. M. S., Vol. 70, pp. 395-477- 



