46 MR. R. COLLETT ON PHYLLOSCOPUS BOREALIS. [Feb. 6, 
ductive of those insects, my investigation of their general habits 
was rendered extremely difficult. It was absolutely impossible to keep 
still a moment, the veil not only affording insufficient protection 
against their continuous attacks, but being in other respects obstructive 
to minute observation. 
The food, too, of Ph. borealis, at this season of the year, would 
seem to be wholly taken from these countless myriads; and the ven- 
tricles, in all the specimens examined were crammed with these 
insects. There are at least half a dozen species of these mosquitos, 
all more or less numerous, though some outnumber the others in 
particular localities. 
On one occasion (July 22) I may have been close to a nest, on 
the Pasvig Elv, near Lake Tschoalme-javre, South Varanger. Both 
the parent birds exhibited unmistakable signs of alarm; but here, 
too, the mosquitos prevented me from finding the nest. A female 
shot in another locality on the same river had large incubation-spots. 
I prepared in all 5 specimens, 4 of which were males. Both sexes 
were, in regard to colour of plumage, precisely alike. A very slight 
difference was seen in some of the males, the dorsal feathers being in 
some darker than in others, and the eye-stripe in such specimens 
was a trifle whiter. 
They measured as follows :— 
Total length. Wing. Tail. Tarsus. Gape. 
millim. millim. millim, millim. millim. 
3 132 70 92 203 153 
revel sels oe She 67 . 50 
Gimcenon ac 67 484 20 153 
(a hSSRES. onoK 135 71 50 203 16 
Cece ce 123 63 447 20 15 
The female would thus appear to be somewhat smaller than the 
males, a deduction in accordance with Mr. Meves’s measurements of a 
number of specimens obtained at Kopatjevskaja, south of Archangel, 
on the 8th and 9th of August, 1869 (Oefv. Kongl. Vet. Akad. Forh. 
1871, p. 758), whereas, on the other hand, there was a singular 
and almost invariable discrepancy between the Russian and Finmark 
specimens, the latter appearing to have been all somewhat* larger 
than those from Archangel. Middendorff has before observed that 
the back of specimens taken in the middle of the summer, when the 
plumage is somewhat worn and faded, has lost a little of its vivid 
green colour and has acquired a greyer tint ; this was likewise the case 
with all the Finmark specimens, which, besides, scarcely retained a 
trace of the whitish yellow spots at the extremities of the wing- 
coverts that inautumn and early spring give to the wings a yellowish 
band. The first primary in one specimen was a trifle shorter than the 
coverts, in the others of the same length, or very little (1 millim.) 
longer. 
The synonymy and general distribution of the species I shall 
refrain from dwelling upon here, my friend Mr. Dresser purposing, 
I understand, to treat upon that subject at large in his great work 
