It has been before observed, that there are two broods of the insect in a season; thus, those which do not emerge from the gall in September remain on till the following April or May. This is a wise provision of nature for continuing the species, should anything befall the autumn brood; and it is the more deserving of notice, because the gall-producing _cynips_ has a deadly enemy which accompanies or follows it in its flight from bud to bud, and deposits an egg wherever it finds the egg of the _cynips_. Here, as soon as the _cynips_ larva is hatched, the larva of the parasite is hatched also; forthwith the latter proceeds to eat a hole in the skin of the rightful occupant of the nidus, and the two larvæ go on growing together till the _cynips_ is ready to assume the pupal state; then the parasite cuts the vital thread of the _cynips_, and uses its skin for a pupal envelope for itself; and thus, instead of the gall-fly emerging into day, a beautiful green insect makes its appearance on the stage of life. I had the pleasure of first discovering this parasite while engaged in studying the _cynips_; it belongs to the genus _Callimone_, and from the fact of having discovered it in Devonshire, I gave it the name of _Callimone Devoniensis_. It is one of the handsomest of our British insects; its costume a brilliant green, shot with gold; the abdominal segments green, gold, and purple; legs yellow; tarsi reddish; and it has four beautiful transparent and iridescent wings.