vii AEPRACTING QUEENS 127 
In some nests I tried a longer course of treat- 
ment, but found that after about three weeks’ 
confinement, sometimes less, the colony ceased to 
thrive, and signs of degeneration began to appear, 
the larva failing to grow to full size and delaying 
to spin their cocoons. The particular cause of this 
trouble was not ascertained, but it may be that the 
larval food contains something that is gathered in 
the fields besides honey and pollen, or that the 
workers are unable to prepare this food properly 
without exercise. It was noticed that a small colony 
throve better and longer in confinement than a 
populous one, and that the pollen-storing species 
lapidarius and terrestris were less quickly affected 
than the pocket-maker, /atrezllellus. A weak colony 
of sy/varum was confined twice with good results. 
In the domiciles occupied by ¢apzdarzus colonies, 
as soon as the workers became busy and the queens 
ceased to fly I reduced the size of the hole in the 
mouse-excluder so that it would also exclude the 
parasite Pstthyrus rupestris. Yo deter wax-moth 
and Brachycoma | relied upon balls of naphthaline, 
placing two or three of these in the grass close to 
the mouth of the hole and eight or ten around the 
wooden cover, but I found that these did not keep 
out the little Phora vitripenntis. 
I was pleased to find that the loss of nests in my 
artificial domiciles, though great, was, so far as I 
could ascertain, much less than that which occurred 
in nature. In the proximity of my domiciles I had 
discovered five nests commencing in natural holes, 
