An Account of the Bird-lice of the Genus Docophorus. 155 
Gluss Voe, 20:1:13, A. Williamson, 7 g, 119: Jan. 1913, 38 ¢. 34 9, 
25 ©. 
From Uria troile, with D. calvus, Kell.—Ronas Voe, 23 :1i1:11, ¢. 
Besides the above five species I have a single ?, D. cordiceps, P. (not uncommon 
on various species of Charadriide), taken with D. merguli on WM. alle, 
Gluss Voe, 20:1:13. -Mr H. M‘Kay has also sent me a 4 example of 
D. icterodes, N (attached to Anatide chiefly) from A. torda, Aberlady, 
29 :1:10 (Ritchie). 
These auk Docophort represent two types—(a) acutrpectus, calvus and 
celedoxus; (b) megacephalus and mergult. The above records enumerate 
564 examples of class (a) from 23 hosts, and 526 examples of class (6) 
from 21 hosts. On such a basisit seems fair to compare the proportions 
of the sexes. It is interesting to note that in the first section the males 
ageregate about 40 °/, of the mature examples, in the second nearly 
50 °/o, we im the “calvus” group the females outnumber the males 
as 3:2,in the “megacephalus” group the sexes are approximately equally 
divided. 
The number of Mallophaga to be expected on a host, as well as the 
regulating conditions of their occurrence, form an obscure subject. Of 
Docophorus alone, anything up to 50 specimens or rather over may be 
regarded as normal, and taking the concomitant Mirmus and Menopon into 
the reckoning, 100-120 may not be an excessive estimate of the mallophagous 
parasites of a bird before the moult. Many of the above records are 
exhaustive for the individuals to which they refer, but more than once 
hosts have been found covered with parasites, but unfortunately at times 
when a complete enumeration was impracticable. Young birds before the 
first moult appear to suffer most ; next come those examples which float 
ashore to die. But after moulting, birds may be found as clean as the 
most fastidious small passerine. 
Ill health and emaciation do not always mean a large mallophagous 
population. I have frequently noticed that where the tick (Jvodes 
putus, Cambr.) is present in force no Mallophaga can be found, though the 
presence of a few examples of Jwodes seems in no way deterrent. On 
10:xi:13, a pair of young Puffins, evidently a late hatching, were secured 
in Yell Sound together. These birds were in extremely poor condition and 
much smaller than average birds of the year. One harboured J. calvus, 
D. celedoxus and D. acutipectus ; the other provided no Mallophaga, but the 
head in front of the eyes was, a few hours after death, covered with a 
scum of mites. 
