An hour was spent in this way, and even then we should not have given up the chase if the sun had not ceased to shine on the bank, and the insects had therefore moved beyond our reach, so as to be within its influence. Lucien, vexed at their going away, and l'Encuerado, furious at having been conquered by the agile creatures, commenced throwing stones at them with the hope of wounding one. Even in this they did not succeed, so l'Encuerado satisfied himself by calling them fools, a name which, in his opinion, constituted a gross insult. About twenty tadpoles, swimming in a puddle of water, were taken by Lucien for fish. "They are frogs," I said to him. "Where are their feet, then?" "Under the brown skin, which makes them look like fish; when the time of their metamorphosis arrives, this skin will split all down their back, and a little frog will come out of it. Look at this tadpole I have just caught; you can see the feet through its transparent skin. To-day it is a fish, that is to say, it breathes through gills--those little tufts you see on each side of its head--and perhaps to-morrow it will undergo that metamorphosis which will cause it to breathe through its mouth. The Toltecs, the great nation which preceded the Aztecs in Mexico, counted the frog among their gods." When putting the tadpole back into the pool, I noticed some whitish insects, which were incessantly rising in jerks to the surface of the water, and diving down again directly. Lucien, astonished at their movements, cried out-- "But, papa, they are walking on their backs!" "You are quite right; they are hydrocorises, allied to the tettigones, and consequently _hemipterae_." The young naturalist was more successful than in his gyrin-hunting, and succeeded in catching two or three of these water-bugs. "What is the use of their wings?" he inquired. "Why, to fly with, and to move from place to place." "Then water-bugs are really able to fly, swim, and walk?" "Yes; and I'm sure they can see in the dark, too," said l'Encuerado, who, it may be remembered, envied animals this privilege. "We are certainly justified in thinking so," I answered, smiling, "for they nearly always choose the night for travelling. Take care they don't bite you, for the water-bug bites as hard as its kinsmen of the woods and houses." A little farther on, Lucien stopped in front of an herbaceous plant, covered from top to bottom with round, flat black insects, speckled with red, and almost resembling mosaic-work. He was very proud of his beautiful discovery, and took hold of two or three of the insects; but feeling their soft bodies give way in his fingers, he threw them down with disgust. "Oh! what are these horrid creatures?" "They are wood-bugs," replied Sumichrast; "only they are in the state of _larvae_, and have no wings." "What has caused this nasty smell on my fingers?" "When any one touches these insects, a very strong-smelling yellowish liquid always exudes from them."