"Oh yes," said Dick, "they are galls caused by a little grub which afterwards turns into a fly."
"They are very pretty things to be caused by a dirty little grub," said Jimmy; "and pray what causes this cuckoo-spit?" pointing to one of the little lumps of water foam which are so common on plants and grasses in the summer.
Dick said they were caused by the larvæ of a fly like the galls, but as they were puzzled to know how it produced this casing of spit, when they got back to Norwich they went into the library and found, in a number of Science Gossip, the following information about it:—
"The larvæ, as soon as it is hatched commences operations on some juicy stem or leaf, no matter what, so it be sappy enough; thrusts in its long proboscis; pumps up the sap; blows it off in small bubbles through a pipe in its tail, and so speedily constructs for itself a cool, moist, translucent home. By and by the sap dries up, and the insect changes its form and becomes winged."
Oak-Gall-Fly.
It was now getting dusk, and the gulls were flying low over the meadows, hawking about like swallows. The boys went to see what they were catching, and saw that they were feeding on the ghost-moths which were hovering over the grass-tops with that vibrating and ghost-like flight which is so peculiar to them. Every country boy must know the ghost-moths which, large and small, white and yellow, hover over the hay-fields in the month of June. Their size alone makes them conspicuous, and they have a weird look as they flit about in the warm, still twilight.
Dick got several for his collection, and then it was time to be returning; and after making due acknowledgment to the friendly keeper they drove back through the quiet night, while nightingales sang around them, and the great red moon rose over the eastern woods, and quenched the pale light of the stars. The horses went well together, and they had no trouble with them; and when they got back to the hotel they went to bed, declaring they had spent a very jolly day.