If I did but know the exact date at which Ammophila hirsuta leaves the cocoon it would greatly help me; but, to my deep regret, I do not. My notes, gathered day by day, show the confusion inseparable from researches that are generally dealing with points that cannot be foreseen, and are silent on this point, whose importance I fully realise now that I want to arrange my materials in order to write these lines. I find mention of the Ammophila of the sands coming out of the egg on June 5, and A. argentata on the 20th; but I have nothing in my archives regarding the hatching of A. hirsuta. It is a detail left unnoticed through forgetfulness. The dates for the two other species accord with the general law, the perfect insect appearing at the hot time of year. By analogy I fix the same date for the coming forth of A. hirsuta from the cocoon. Whence, then, come those which one sees at work on their burrows at the end of March and April? We must conclude that they were hatched in the previous year and emerged from their cells at the usual time in June and July, lived through the winter, and began to build as soon as spring came. In a word, they are insects that hibernate. Experience fully confirms this conclusion. Do but search patiently in a vertical bank of earth or sand well exposed to the sun, especially where generations of the various honey-gathering Hymenoptera have followed one another year after year, riddling the ground with a labyrinth of passages till it looks like a huge sponge, you are nearly sure to see in the heart of winter A. hirsuta either alone or in little parties of three or four, crouched in some warm retreat, waiting inactive till summer shall come. This cheering little meeting, amid the gloom and cold of winter, with the graceful insect which at the first notes of the bunting and the cricket enlivens the grassy paths, is one that I have been able to enjoy at will. If the weather be calm and the sun has a little power, the chilly insect comes out to bask on its threshold, luxuriating in the hottest beams, or it will venture timidly outside and walk slowly over the spongy bank, brushing its wings. So, too, does the little gray lizard, when the sun begins to warm the old wall which is its home. But vainly would one seek in winter, even in the most sheltered spots, for a Cerceris, Sphex, Philanthus, Bembex, and other Hymenoptera with carnivorous larvæ. All died after their autumn labours, and their race is only represented by the larvæ benumbed down in their cells. Thus, by a very rare exception, Ammophila hirsuta, hatched in the hot season, passes the following winter in some warm refuge, and this is why it appears so early in the year.