We did not learn from the natives that anacondas
over twenty feet long had been seen on the Napo, but specimens twice
that size are found on the Amazon. Land boas do not often exceed fifteen
feet in length.

[Footnote 131: The specific name was strangely given for its habit, when
young, of darting upon mice. Anaconda is a Ceylonese word.]

[Illustration: A Howler.]

Gangs of the large howling monkeys often entertained us with their
terrific, unearthly yells, which, in the truthful language of Bates,
"increased tenfold the feeling of inhospitable wildness which the forest
is calculated to inspire." They are of a maroon color (the males wear a
long red beard), and have under the jaw a bony goitre--an expansion of
the os hyoides--by means of which they produce their loud, rolling
noise. They set up an unusual chorus whenever they saw us, scampering to
the tops of the highest trees, the dams carrying the young upon their
backs. They are the only monkeys which the natives have not been able to
tame. Vast numbers of screaming parrots and macaws flew over our heads,
always going in pairs and at a great height. Groups of "gypsy-birds"
were perched on the trees overhanging the river, and black ducks,
cormorants, and white cranes floated on the water or stalked along the
plaias.

But one form of life superabounded. From the rising of the sun to the
going down thereof clouds of ubiquitous sand-flies filled our cabin,
save when the wind was high. As soon as the sand-flies ceased, myriads
of musquitoes began their work of torture, without much preparatory
piping, and kept it up all night.[132] These pests were occasionally
relieved or assisted by piums--minute flies that alight unnoticed, and
squatting close to the skin, suck their fill of blood, leaving dark
spots and a disagreeable irritation. Our hands were nearly black with
their punctures. We also made the acquaintance of the montuca, a large
black fly whose horny lancets make a gash in the flesh, painless but
blood-letting. All these insects are most abundant in the latter part of
the rainy season, when the Maranon is almost uninhabitable. The
apostrophe of Midshipman Wilberforce was prompted by sufferings which we
can fully appreciate: "Ye greedy animals! I am ashamed of you. Can not
you once forego your dinner, and feast your mind with the poetry of the
landscape?" Right welcome was the usual afternoon squall, which sent
these pests "kiting" over the stern.

[Footnote