874 



U. S. p. E. E. EXP. AND SUEVEYS — ^ZOOLOGY — GENEEAL EEPOET. 



of other species are devoured hj them wlieii left unprotected. They do not dive, hut rest 

 lightly upon the water, and rise easily from its surface. 



A second species of 2'achypetes, T. palmerstonii, is admitted hy some authors and denied by 

 others. 



List of specimens. 



