Annals of the Transvaal Mtjseum, 
229 
introduced for the sake of lucidity in the use of a common ratio (expressed 
by the sign %) in all cases where comparisons of the lengths of feathers are 
made. Reference is also made to the liability of members of a group to 
change in shade of colour of markings according to season, as it does not 
seem to be generally known that some species change to a great extent 
while others hardly do so at all. 
To show the uniformity existing amongst individuals of the same age 
and sex, collected at the same season, measurements of all the specimens 
examined are tabulated. The actual length of the first primary is tabulated 
in the case of C. terrestris and C. lavendulae on account of the likelihood 
of their being confused with some species of Hemipteryx. 
Measurements given in the tables have been taken in the following 
manner 
Wing . — From the bend of the wing to the tip of the longest primary, 
the quills being pressed down on the callipers and straightened out as 
much as possible without injury to the specimen. 
Tail .— From the base of the middle tail feathers to the tips. 
Tarsus. — Posteriorly, from the top of the bone to the base of the hind 
toe. 
Culmen . — From the end of the ridge (hidden amongst the feathers) 
to the tip, in a straight line. 
First primary . — From the base to the tip, without straightening the 
feather ; the second primary is measured from the same spot on the base 
of the first primary to the tip of the second, without straightening the 
feather. 
Middle toe. — Dorsally, with the toe straightened as much as possible, 
from a point opposite the web joining the middle to the outer toe, to the 
base of the claw. 
Key to the South African Species of Cistieolinae. 
1. Tail without distinct dark subterminal mark 2. 
Tail with distinct dark subterminal mark 3. 
2. Tail shorter than wing, breast blue-grev C. fulvicapilla, p. 231. 
Tail shorter than wing, breast whitish C. ruficapilla , p. 232. 
Tail longer than wing. C. aberrans, p. 236. 
3. Tail over 50 mm. in length 4. 
Tail under 50 mm. in length 12. 
4. Back streaked 5. 
Back plain, greyish C. semitorques , p. 251. 
Back plain, olive brown or rufous (in young 
obscurely streaked) C. erythrops, p. 254. 
5. Tarsus over 23 mm C. natalensis, p. 252. 
Tarsus under 24 mm 6. 
