72 PHYSIOLOGY OF THE HONEY-BEE. 
To return to Bevan: 
169. “ When it has undergone this change, it has usually borne 
the name of nymph, or pupa. It has now attained its full growth, 
and the large amount of nutriment which it has taken serves as 
a store for developing the perfect insect. 
“The working-bee nymph spins its cocoon in thirty-six hours. 
After passing about three days in this state of preparation fora 
new existence, it gradually undergoes so great a change as not 
to wear a vestige of its previous form.” 
Fig, 29. 
SPINNING OF THE COCOON AND TRANSFORMATION INTO NYMPH. 
(Magnified. From Sartori and Rauschenfels.) 
170. The last cast-off skin of the larva, ‘‘ which, by the 
creature’s movements within the cell, becomes plastered to 
the walls and joins the cocoon near the mouth end ’’ (Chesh- 
ire), is left behind, and forms a closely-attached and exact 
lining to the cell; by this means the breeding-cells become 
smaller, and their partitions stronger, the oftener they 
change their tenants. 
So thin is this lining, that brood combs more than twenty 
years old have been found to raise bees apparently as large 
as any other in the Apiary. 
171. About twenty-one days are usually required for the 
ransformations from the worker-egg to the perfect insect. 
But the time may be shortened or lengthened by the tem- 
perature, or the conditions of the colony. Dzierzon and 
others wrote that a worker-bee can hatch in nineteen to 
twenty-one days. Collin says nineteen to twenty-three. 
That the brood can remain even longer before hatching, is 
