Adapted from Jim Conrad's online book A Birding Trip through Mexico, This excerpt from "The Pine Forest of Lake Arareko" near Copper Canyon
ATTACK FROM ABOVE
For an hour the pines and rock outcrops rimming the canyon glow in sunlight and the blue sky dazzles with its clarity, but the canyon itself remains chilly, shadowy, and somber. At mid morning, still in the shadows, warm breezes begin stirring. Hot air is supposed to rise but, here, air feeling warm and dry and smelling of pine appears to be draining from the canyon's head and flowing down the canyon, streaming around the chimney rock and me. And this strange wind is bringing me visitors...

They are stink bugs. Brown, shield-shaped hemipterids of the family Pentatomidae, hoards of them, not lazily drifting with the warm currents, but flying hard with the current, as if embarked on stink-bug kamikaze missions. They thump into the tent, against the pine, and against me, my legs, chest, and face. They roll to the ground, flounder struggling to get upright, and if their flailing legs happen to snag something they yank themselves onto their bellies and immediately fly off again. Soon the ground is littered with them and if I nudge one with a finger the finger ends up smelling like the nauseating stinkbug defense.

No sooner has the invasion subsided than another onslaught begins, this time conducted by black, plump, two-millimeter-long (±1/12th inch), blood-sucking black flies -- Dipterids, probably of the family Simuliidae. They swarm around ankles, arms, neck, and face, and do not diminish in numbers once sunlight arrives. They become a plague with repellent keeping them away only a few minutes. Atop my chimney, as the canyon at last receives its full share of sunlight, I sit fuming over the godly humor that sets a mind so acutely alert and informed in a body that, by virtue of its very nature, draws black flies that make elevated thought impossible.