The Bruchus knows neither the fatigues of the laborious, obliged to limit the size of her family, nor the misfortunes of the parasite, obliged to produce an exaggerated number of offspring.  Without painful search, entirely at her ease, merely moving in the sunshine over her favourite plant, she can ensure a sufficient provision for each of her offspring; she can do so, yet is foolish enough to over-populate the pod of the pea; a nursery insufficiently provided, in which the great majority will perish of starvation.  This ineptitude is a thing I cannot understand:  it clashes too completely with the habitual foresight of the maternal instinct.

I am inclined to believe that the pea is not the original food plant of the Bruchus.  The original plant must rather have been the bean, one seed of which is capable of supporting half a dozen or more larvae.  With the larger cotyledon the crying disproportion between the number of eggs and the available provision disappears.

Moreover, it is indubitable that the bean is of earlier date than the pea.  Its exceptional size and its agreeable flavour would certainly have attracted the attention of man from the remotest periods.  The bean is a ready-made mouthful, and would be of the greatest value to the hungry tribe.  Primitive man would at an early date have sown it beside his wattled hut.  Coming from Central Asia by long stages, their wagons drawn by shaggy oxen and rolling on the circular discs cut from the trunks of trees, the early immigrants would have brought to our virgin land, first the bean, then the pea, and finally the cereal, that best of safeguards against famine.  They taught us the care of herds, and the use of bronze, the material of the first metal implement.  Thus the dawn of civilisation arose over France.  With the bean did those ancient teachers also involuntarily bring us the insect which to-day disputes it with us?  It is doubtful; the Bruchidae seem to be indigenous.  At all events, I find them levying tribute from various indigenous plants, wild vegetables which have never tempted the appetite of man.  They abound in particular upon the great forest vetch (Lathyrus latifolius), with its magnificent heads of flowers and long handsome pods.  The seeds are not large, being indeed smaller than the garden pea; but eaten to the very skin, as they invariably are, each is sufficient to the needs of its grub.

We must not fail to note their number.  I have counted more than twenty in a single pod, a number unknown in the case of the pea, even in the most prolific varieties.  Consequently this superb vetch is in general able to nourish without much loss the family confided to its pod.

Where the forest vetch is lacking, the Bruchus, none the less, bestows its habitual prodigality of eggs upon another vegetable of similar flavour, but incapable of nourishing all the grubs:  for the example, the travelling vetch (Vicia peregrina) or the cultivated vetch (Vicia sativa).  The number of eggs remains high even upon insufficient pods, because the original food-plant offered a copious provision, both in the multiplicity and the size of the seeds.  If the Bruchus is really a stranger, let us regard the bean as the original food-plant; if indigenous, the large vetch.