(d) The imago or winged insect.—When the internal organs of the butterfly are completed, the pupal skin splits, and the perfect insect comes out. Look for pupae between September and March, or in July, and try to see the transformation. Notice the method of flight of the butterfly, and the position in which the wings are held when it settles. At what time of the day, and in what kind of weather, have you seen cabbage-whites flying? Kill a butterfly by putting it into a bottle containing crushed laurel leaves, or a few lumps of potassium cyanide (a deadly poison) wrapped in blotting paper, and examine it closely. [Pg 364] (i) The head.—Notice the large, compound eyes, the knobbed feelers, the long and coiled proboscis, and the labial palps (which look like tusks). (ii) The thorax.—The true form of the thorax and abdomen is concealed by the hairs which clothe the body. Wet the body with methylated spirit to make the hairs lie down. Notice that the first and third segments of the thorax are very small, while the middle segment, which carries the fore-wings, is large. Observe that the fore-wings are not modified into wing-covers, but are, generally speaking, much like the hind-wings. Determine the sex of the specimen by means of Fig. 225. Notice that, when you touch a wing, a little white dust comes off on your finger; the dust consists of very small scales. Do both surfaces of the wings bear scales? With a rather stiff camel-hair brush, brush the scales from the wings of one side. What markings have been removed, and what new markings have been made clear, by the removal of the scales? How many legs has the butterfly? (iii) The abdomen.—Count the segments. 2. The tiger moth.—In early summer examine lettuce, strawberry, and nettle leaves for “woolly bears”—the hairy caterpillars of the tiger moth. Keep these in the breeding-cage with the food-plants, and observe and describe their appearance and habits. How do they behave when alarmed? Watch them spin their cocoons (pupa cases) about the end of June, and describe the process. Examine the pupa, and state in what respects it differs from the caterpillar. About the end of July watch for the emergence of the perfect moth. Notice the position of the wings of a resting moth. Are they held like those of a butterfly? Kill and examine the moth, and compare it further with a butterfly. Especially notice (a) That the feelers of the tiger moth are not knobbed at the ends, but are either thread-like (in the female) or comb-like (in the male); and (b) That a bristle at the base of the hind-wing hooks on a catch in the fore-wing of the same side.