be inevitable. But we can leave this small matter unsettled
pending further information.

The fact remains that females, females exclusively, have come out of the
eggs laid in May. They have descendants, of that there is no room for
doubt; they procreate though there are no males in their time. From
this generation by a single sex, there spring, two months later, males
and females. These mate; and the same order of things recommences.

To sum up, judging by the three species that form the subject of my
investigations, the Halicti have two generations a year: one in the
spring, issuing from the mothers who have lived through the winter after
being fecundated in the autumn; the other in the summer, the fruit of
parthenogenesis, that is to say, of reproduction by the powers of the
mother alone. Of the union of the two sexes, females alone are born;
parthenogenesis gives birth at the same time to females and males.

When the mother, the original genitrix, has been able once to dispense
with a coadjutor, why does she need one later? What is the puny idler
there for? He was unnecessary. Why does he become necessary now? Shall
we ever obtain a satisfactory answer to the question? It is doubtful.
However, without much hope of succeeding we will one day consult the
Gall-fly, who is better-versed than we in the tangled problem of the
sexes.

INDEX.

Alpine Odynerus.

Amadeus' Eumenes.

Ammophila (see also Hairy Ammophila).

Andrena.

Andrenoid Osmia.

Ant.

Anthidium (see the varieties below, Cotton-bee, Resin Bee).

Anthidium bellicosum.

Anthidium cingulatum (see Girdled Anthidium).

Anthidium diadema (see Diadem Anthidium).

Anthidium florentinum (see Florentine Anthidium).

Anthidium Latreillii (see Latreille's Resin-bee).

Anthidium manicatum (see Manicate Anthidium).

Anthidium quadrilobum (see Four-lobed Resin-bee).

Anthidium scapulare (see Scapular Anthidium).

Anthidium septemdentatum (see Seven-pronged Resin-bee).

Anthocopa papaveris (see Upholsterer-bee).

Anthophora (see also Anthophora of the Walls, Hairy-footed Anthophora,
Masked Anthophora).

Anthophora of the Walls.

Anthophora parietina (see Anthophora of the Walls).

Anthophora pilipes (see Hairy-footed Anthophora).

Anthrax (see Anthrax sinuata).

Anthrax sinuata.

Aphis (see Plant-louse).

Archimedes.

Augustus, the Emperor.

Bee.

Beetle.

Bembex.

Black, Adam and Charles.

Black Plant-louse.

Black