_The Distribution of Butterflies._--Butterflies are found everywhere that plant life suited to the nourishment of the caterpillars is found. There are some species which are arctic and are found in the brief summer of the cold North and upon the lofty summits of high mountains which have an arctic climate. Most of them are, however, children of the sun, and chiefly abound in the temperate and tropical regions of the earth. While the number of species which are found in the tropics vastly exceeds the number of species found in the temperate zone, it is apparently true that the number of specimens of certain species is far more numerous in temperate regions than in the tropics. Very rarely in tropical countries are great assemblages of butterflies to be seen, such as may be found in the summer months in the United States, swarming around damp places, or hovering over the fields of blooming clover or weeds. In the whole vast region extending from the Rio Grande of Texas to the arctic circle it is doubtful whether more than seven hundred species of butterflies are found. On the continent of Europe there are only about four hundred and fifty species. The number of species of butterflies and the number of species of birds in the United States are very nearly the same.
THE CAPTURE, PREPARATION, AND PRESERVATION OF SPECIMENS
"What hand would crush the silken-wingèd fly, The youngest of inconstant April's minions, Because it cannot climb the purest sky, Where the swan sings, amid the sun's dominions? Not thine."
"Do not mash your specimens!"--THE PROFESSOR.
[Illustration FIG. 43.--Plan for folding net-ring: _c_, halves of ring detached; _b_, upper joint of the halves; _a_, ring set; _d_, cap of ferrule; _f_, cap of ferrule, showing screw in place; _e_, screw (Riley).]