260 



Proceedings of the Royal Physical Society. 



whence, as I learn from Kellogg's "List of the Biting Lice (Mallophaga) 

 taken from Birds and Mammals of North America," 1 N. citrinus, Nitzsch, 

 has been recorded from it by Osborn. My specimens, however, agree 

 much better — so well, indeed, that I cannot doubt their identity — with 

 N. maritimus, Kellogg and Chapman, described in 1899,' 2 from several 

 species of Pacific Alcidas closely related to our Little Auk. Whether this 

 is really different from Denny's N. alcce from the Razorbill, which Giebel 

 and others have, too hastily perhaps, treated as synonymous with Nitzsch's 

 N. citrinus from the same bird, I have no adequate means of judging. 

 As Kellogg and Chapman point out, Piaget describes and figures citrinus 

 as having the posterior margin of the metathorax rounded, not angular, 



Fig. 1. Fig. 2. Fig. 3. 



Docophorus merguli, 9 Nirmus maritimus, 9 Menopon lutcscens 1 , 9 



The lengths of the specimens figured are 1"7, 1'8, and 1*4 respectively. 



a character they make use of in differentiating their maritimus from it; 

 and certainly the only Nirmus (N. citrinus I consider it) I have from 

 the Common Guillemot shows practically no angle. Denny depicts his 

 alcce with the metathorax angled posteriorly, which would therefore seem 

 to preclude its identity with citrinus and to point to the possibility of 

 its being the same as maritimus, though his figure suggests a broader 

 insect. Unfortunately I have no sufficiently well preserved Nirmus from 

 the Razorbill with which to critically compare those from the Little Auk, 

 I therefore name the specimens from the latter N. maritimus, K. and C, 

 leaving the alcce question to others to settle. 



3. The Menopon. — No species of this genus appears to have been 

 recorded from the Little Auk. Of the three genera I found on them, tins 



1 Pin,. U.S. Nat. Ma*., xxii., p. 52, 1899. 



'-' " New Mallophaga, 1 1 1.," Occasional Papers Galifornian Acad. Sci., vi., p. 72, 1899. 



