my fingers and thumbs, to the great detriment of my travellers;
for I could easily warp their wing-joints and thus weaken their flight.
It was worth while improving the method of operation, both in my own
interest and in that of the insect. I must mark the Bee, carry her to a
distance and release her, without taking her in my fingers, without
once touching her. The experiment was bound to gain by these nice
precautions. I will describe the method which I adopted.

The Bee is so much engrossed in her work when she buries her abdomen
in the cell and rids herself of her load of pollen, or when she is
building, that it is easy, at such times, without alarming her, to mark
the upper side of the thorax with a straw dipped in the coloured glue.
The insect is not disturbed by that slight touch. It flies off; it
returns laden with mortar or pollen. You allow these trips to be
repeated until the mark on the thorax is quite dry, which soon happens
in the hot sun necessary to the Bee's labours. The next thing is to
catch her and imprison her in a paper bag, still without touching
her. Nothing could be easier. You place a small test-tube over the Bee
engrossed in her work; the insect, on leaving, rushes into it and is
thence transferred to the paper bag, which is forthwith closed and
placed in the tin box that will serve as a conveyance for the whole
party. When releasing the Bees, all you have to do is open the bags. The
whole performance is thus effected without once giving that distressing
squeeze of the fingers.

Another question remains to be solved before we go further. What
time-limit shall I allow for this census of the Bees that return to
the nest? Let me explain what I mean. The dot which I have made in
the middle of the thorax with a touch of my sticky straw is not very
permanent: it merely adheres to the hairs. At the same time, it would
have been no more lasting if I had held the insect in my fingers. Now
the Bee often brushes her back: she dusts it each time she leaves the
galleries; besides, she is always rubbing her coat against the walls of
the cell, which she has to enter and to leave each time that she brings
honey. A Mason-bee, so smartly dressed at the start, at the end of
her work is in rags; her fur is all worn bare and as tattered as a
mechanic's overall.

Furthermore, in bad weather, the Mason-bee of the Walls spends the days
and nights in one of the cells of her dome, suspended head downwards.
The Mason-