enters, especially on the lower floors.
This seems to me rather insanitary. To avoid the humidity, or for other
reasons which escape me, the Solenius does not dig very far into her
bramble-stump and consequently can stack but a small number of cells in
it. A series of five cocoons gives me first four females and then one
male; another series, also of five, contains first three females, with
two males following. These are the most complete that I have for the
moment.

I reckoned on the Black Psen, or Psen atratus, whose series are pretty
long; it is a pity that they are nearly always greatly interfered with
by a parasite called Ephialtes mediator. (Cf. "The Life of the Fly":
chapter 2.--Translator's Note.) I obtained only three series free
from gaps: one of eight cocoons, comprising only females; one of six,
likewise consisting wholly of females; lastly, one of eight, formed
exclusively of males. These instances seem to show that the Psen
arranges her laying in a succession of females and a succession of
males; but they tell us nothing of the relative order of the two series.

From the Spider-huntress, Trypoxylon figulus, I learnt nothing
decisive. She appeared to me to rove about from one bramble to the next,
utilizing galleries which she has not dug herself. Not troubling to be
economical with a lodging which it has cost her nothing to acquire, she
carelessly builds a few partitions at very unequal heights, stuffs
three or four compartments with Spiders and passes on to another
bramble-stump, with no reason, so far as I know, for abandoning the
first. Her cells, therefore, occur in series that are too short to give
us any useful information.

This is all that the bramble-dwellers have to tell us; I have enumerated
the list of the principal ones in my district. We will now look
into some other Bees who arrange their cocoons in single files: the
Megachiles (Cf. Chapter 8 of the present volume.--Translator's Note.),
who cut disks out of leaves and fashion the disks into thimble-shaped
receptacles; the Anthidia (Cf. Chapters 9 and 10 of the present
volume.--Translator's Note.), who weave their honey-wallets out
of cotton-wool and arrange their cells one after the other in some
cylindrical gallery. In most cases, the home is the produce of neither
the one nor the other. A tunnel in the upright, earthy banks, the old
work of some Anthophora, is the usual dwelling. There is no great depth
to these retreats; and all my sear