128 
DRONE ORGANS. 
from the ovum in a marked manner. Whereas in the 
ovum there is a cell substance and a nucleus, in the 
spermatozoon the cell substance is reduced to a 
minimum. Geddes ( 45 ) says it is of a definite 
type, and has a minute ‘ head,’ consisting almost en- 
tirely of nucleus and a long 'contractile tail, which, 
working behind like a screw, propels the essential 
‘ head ’ through the water, or ducts. In shape it 
somewhat resembles the ‘great reed-mace,’ commonly 
called ‘ bulrush.’ 
The vasa differentia are narrow tubes, which, after 
several spiral turns, join the seminal vesicles, con- 
nected at their narrower extremities to the mucus 
gla?ids {b b). These secrete a gelatinous fluid, which 
hardens and gives the spermatozoa cohesive power. 
The seminal vesicles at the entrance to the mucus 
glands unite with the ductus ejaculatorius {c\ which is 
provided with well-developed muscular walls, acting in 
forcing forward the spermatozoa. The rounded fleshy 
white body is called the bean.^ or lentil (d)^ united by 
two crescent-shaped scales, and two triangular ones, 
which Girard says are rudiments of the genital arma- 
ture {ar 7 nor copulatrix) of the hymenoptera. The 
bean and the remaining parts are surrounded by a 
membranous covering. Below the bean on the 
covering are found five or six brown ridges ; these are 
curved tubercles covered with stiff hairs, which pre- 
vent the withdrawal of the organ from the vagina of 
the queen, and aid in its rupture. The spermatozoa 
are forced into the bean, which they fill, and their 
mass is now called the spermatophore. 
