A Leucopsis (Cf. "The Mason-bees": chapter 11.--Translator's Note.) inserts her eggs through the cement wall of our three Chalicodomae. I know her under two names. When she comes from the Chalicodoma of the Pebbles or Walls, whose opulent larva saturates her with food, she deserves by her large size the name of Leucopsis gigas, which Fabricius bestows upon her;when she comes from the Chalicodoma of the Sheds, she deserves no more than the name of L. grandis, which is all that Klug grants her. With a smaller ration "the giant" is to some degree diminished and becomes no more than "the large." When she comes from the Chalicodoma of the Shrubs, she is smaller still; and, if some nomenclator were to seek to describe her, she would no longer deserve to be called more than middling. From dimension 2she has descended to dimension 1 without ceasing to be the same insect, despite the change of diet; and at the same time both sexes are present in the three nurselings, despite the variation in the quantity of victuals.
I obtain Anthrax sinuata ("The Mason-bees": chapters 8, 10 and 11.--Translator's Note.) from various bees' nests. When she issues from the cocoons of the Three-horned Osmia, especially the female cocoons, she attains the greatest development that I know of. When she issues from the cocoons of the Blue Osmia (O. cyanea, KIRB.), she is sometimes hardly one-third the length which the other Osmia gives her. And we still have the two sexes--that goes without saying--and still identically the same species.
Two Anthidia, working in resin, A. septemdentatum, LATR., and A.
bellicosum, LEP. (For these Resin-bees, cf. "Bramble-bees and Others":
chapter 10.--Translator's Note.), establish their domicile in old Snail-shells. The second harbours the Burnt Zonitis (Z. proeusta (Cf. "The Glow-worm and Other Beetles": chapter 6.--Translator's Note.)). Amply nourished this Meloe then acquires her normal size, the size in which she usually figures in the collections. A like prosperity awaits her when she usurps the provisions of Megachile sericans. (For this Bee, the Silky Leaf-cutter, cf. "Bramble-bees and Others": chapter 8.--Translator's Note.) But the imprudent creature sometimes allows itself to be carried away to the meagre table of the smallest of our Anthidia (A. scapulare, LATR. (A Cotton-bee, cf. idem: chapter 9.--Translator's Note.)), who makes her nests in dry bramble-stems. The scanty fare makes a wretched dwarf of the offspring belonging to either sex, without depriving them of any of their racial features. We still see the Burnt Zonitis, with the distinctive sign of the species: the singed patch at the tip of the wing-cases.
And the other Meloidae--Cantharides, Cerocomae, Mylabres (For these Blister-beetles or Oil-beetles, cf. "The Glow-worm and Other Beetles":
chapter 6.--Translator's Note.)--to what inequalities of size are they not subject, irrespective of sex! There are some--and they are numerous--whose dimensions fall to a half, a third, a quarter of the regular dimensions.
Among these dwarfs, these misbegotten ones, these victims of atrophy, there are females as well as males; and their smallness by no means cools their amorous ardour. These needy creatures, I repeat, have a hard life of it.
Whence do they come, these diminutive Beetles, if not from dining-rooms insufficiently supplied for their needs? Their parasitical habits expose them to harsh vicissitudes. No matter: in dearth as well as in abundance the two sexes appear and the specific features remain unchanged.
It is unnecessary to linger longer over this subject. The demonstration is completed. The parasites tell us that changes in the quantity and quality of food do not lead to any transformation of species. Fed upon the larva of the Three-horned Osmia or of the Blue Osmia, Anthrax sinuata, whether of handsome proportions or a dwarf, is still Anthrax sinuata; fed upon the allowance of the Anthidium of the empty Snail-shells, the Anthidium of the brambles, the Megachile or doubtless many others, the Burnt Zonitis is still the Burnt Zonitis. Yet variation of diet ought to be a very potential factor in the problem of progress towards another form. Is not the world of living creatures ruled by the stomach? And the value of this factor is unity, changing nothing in the product.
The same parasites tell us--and this is the chief object of my digression--that excess or deficiency of nutriment does not determine the sex. So we are once more confronted with the strange proposition, which is now more positive than ever, that the insect which amasses provisions in proportion to the needs of the egg about to be laid knows beforehand what the sex of this egg will be. Perhaps the reality is even more paradoxical still. Ishall return to the subject after discussing the Osmiae, who are very weighty witnesses in this grave affair. (Cf. "Bramble-bees and Others":
chapters 3 to 5. The student is recommended to read these three chapters in conjunction with the present chapter, to which they form a sequel, with that on the Osmiae (chapter 2 of the above volume) intervening.--Translator's Note.)
