Bulletin - United States National Museum - si-pddr - Smithsonian ...

22 BUULETIN 133, UNITED STATES NATIONAL MUSEUM
the mountain slopes in little bands, traveling down toward the
plains where they passed on northward. With heavy storms in the
higher reaches, these movements become more pronounced and at
times include hill inhabiting species that temporarily pass down
to the warmer lowlands until the stress of weather has passed.
It was interesting also to observe the migrational movements of
a form of the monarch butterfly {Anosia erippits) that wintered
in numbers in the Chaco, and in spring flew southward to spread
over the pampas.
ANNOTATED LIST OF BIRDS
The following account consists of an annotated list of the species
of birds collected, with observations on a few of which no specimens
were taken. Measurements, made in millimeters, have been taken
by the method usual among present day American ornithologists.
The wing measurement is the chord of the distance from the bend
of the wing (the metacarpal or wrist joint) to the tip of the longest
primary taken with dividers except in large birds where the measurement
is made with a straight rule, but without flattening the wing.
The length of tail, measured with dividers, is the distance from the
base of the median rectrices on the uropygium to the tips of the
longest tail feathers. The culmen has been measured from the base
in all cases except where (as in parrots) it is specified as taken from
the cere, etc. The distance, measured with dividers, is taken in a
straight line from the basal point to the extreme tip. The tarsal
length, likewise taken with dividers, is secured by placing one point
of the instrument at the upper end of the tarsus on its posterior
side, and the other at the end of the middle trochlea of the meta-
tarsus.
With shifts in generic names, so common in our modern nomen-
clature, at times a change is required in the current designation for
a family. Current family names have been derived from the appel-
lation of some genus considered as typical of the group concerned,
in the main from the oldest genus name in the family. Where this
genus name has been changed through the application of the law of
priority in publication, type fixation, or other cause, change in the
family name necessarily follows. Certain ornithologists (mainly in
England) are advocating derivation of a new family name from the
next oldest generic appellation. This, however, may cause confusion
since it may result in shifting the tjq^e genus from a group that
has been held typical of the family concerned, to one that is aberrant
or possibly even to a genus of doubtful allocation. The confusion
that may arise is easily evident. It seems preferable to allow the
same generic group to remain as typical of the family regardless of
change in its appellation; in other words, to allow the family name