Sometimes when the last-mentioned species was suspended over the water, its rapidly vibrating wings showing like a mere film, a speck shot down the valley, swift as an arrow, as white as a snowflake, and stopping suddenly over the pool, startled the emerald-throat, and frightened it up amongst the overhanging branches. The intruder was the white-cap (Microchera parvirostris, Lawr.), the smallest of thirteen different kinds of humming-birds that I noticed around Santo Domingo; being only a little more than two and a half inches in length, including the bill; but it was very pugnacious, and I have often seen it drive some of the larger birds away from a flowering tree. Its body is purplish-red, with green reflections, the front of its head flat and pearly white, and, when flying towards one, its white head is the only part seen. Sometimes the green-throat would hold its ground, and then it was comical to see them hovering over the water, jerking round from side to side, eyeing each other suspiciously, the one wishing to dip, but apparently afraid to do so, for fear the other would take a mean advantage, and do it some mischief whilst under water; though what harm was possible I could not see, as there were no clothes to steal. I have seen human bathers acting just like the birds, though from a different cause, bobbing down towards the water, but afraid to dip their heads, and the idea of comicality arose, as it does in most of the ludicrous actions of animals, from their resemblance to those of mankind. The dispute would generally end by the green-throat giving way, and leaving the pugnacious little white-cap in possession of the pool.