MY DEAR JACK-IN-THE-PULPIT:  No doubt, you have heard of the “leaf-cutter” bees, who line their nests with small round pieces of leaves, which they themselves cut and then fit together so exactly, without gum, that they hold their stores of honey and do not leak a bit.  Well, a sharp-eyed observer has found, on one of these bees, an insect whose body is no longer than the width of the dot of this “i” (1-90th of an inch), and which is believed to be the smallest insect known.  It is called Pteratomus, a word which means “winged atom,” and it lives entirely upon the body of the bee.  It has beautiful hairy wings, and long feelers, and its legs are rather like those of a mosquito, though, of course, very much smaller.  Its feet are so small that they can only just be seen when magnified to four hundred times their natural size!  Now, for a full-grown insect, as it is, I think the Pteratomus is very small.—­Sincerely yours,

    THE LITTLE SCHOOLMA’AM.

[Illustration:  A WATER-SPOUT.]

A WATER-SPOUT.

Did any of you ever hear of water-spouts at sea?  I don’t know much about them myself, but the St. Nicholas artist will draw a picture of one for you, and the editors will kindly put it in.  According to travelers, the water seems to come down from the clouds, or go up from the sea,—­I don’t know which,—­and drives along, through the storm, in a great watery column.  I have heard of whirlwinds, and I think this might be called a “whirl-water.”

THE USES OF HAIR ON PLANTS.

M.E.K. writes, in answer to my question in July, that her “Botany” book says, “Hair on plants seems to afford them security against changes of weather, and plants with hair can stand more heat than bare ones.”  A.W.  Ferris says: 

“If a plant that needs much moisture is dug up from its native wet home and planted in a dry spot, hairs will sprout on it and try to get from the air the moisture that can no longer be drawn from the earth.  But if you put back this plant in its old home, it will lose its hair—­becoming bald.  Sometimes, plant hairs are connected with glands of poisonous liquid, as with the nettle, whose hairs we say ‘sting,’ because of the pain the poison gives when the skin is pricked by them.”

Frances and Margaret Bagley, also, write on this subject, and I’m much obliged to all four.  Besides these letters, I’ve had word that plant-hair is put to the following uses:  On some plants it catches insects and helps to eat them; in others, the hair sends out a kind of juice which keeps away insects that might harm the plant; on the mulleins, the stiff hairs are supposed to prevent cattle from browsing on them; and on yet others, the hairs suck in gases and liquids as part of the food of the plants.  And there may be other uses for these hairs that I haven’t heard of yet.