250 GEO. H. BISHOP 
the variation in the physiological reactions concerned makes it 
difficult to measure accurately the degree of the response."! The 
following table will summarize the data correlating age of the 
drone with the histological and physiological findings. 
3. Manipulation of drones. If a drone’s abdomen is pinched 
sharply between thumb and forefinger, the pressure will generally 
cause partial or complete extrusion of the copulatory organ. 
The penis tube may evert throughout its length, as described 
heretofore, everting the two lateral chitinized plates that enclose 
its bulb, and also drawing the ejaculatory duct through the 
everted bulb (text fig. 2, C);in this case whatever fluid is expressed 
forms a drop at the end of the penis. Extrusion may stop, 
however, before this bulb has turned inside out (text fig. 2, B). 
The fluid will then remain for the most part in the bulb of the 
penis (b) and in the elastic and expanded end of the adjoining 
ejaculatory duct (c). There may be little or no spermatic fluid 
expressed, or the fluid may consist entirely of mucus, or it may 
consist of both mucus and sperm, rarely of sperm alone. 
Selecting drones all of which were known to be old enough to 
function in normal copulation, experiments were undertaken to 
find what controlled the normal protrusion of the organ and the 
normal ejaculation of the secretions. 
It was found almost impossible at first to dissect these drones 
without disturbance of the sexual apparatus. Drones held in 
the hand, without mechanical pressure being applied by the 
fingers, will often extrude the penis with a sort of explosive 
contraction of the abdomen. Even when extrusion does not 
occur, the mucous glands of dissected mature drones will generally 
be found to have burst at the expanded distal end, or else sperm 
and mucus will have been forced into the base of the gland, 
ejaculatory duct, or penis. If the drone’s head is amputated 
a disturbance invariably occurs; frequently this goes as far as 
11 Whether functional maturity and ability to effectually inseminate queens is 
attained at the time of apparent histological and physiological maturity of the 
organs and secretions described, is a matter which only mating experiments can 
determine. Mr. F. W. L. Sladen, apiarist of the Canadian Department of Agri- 
culture, informs me that queens mated to drones under two weeks of age pro- 
duced a large percentage of infertile eggs. (See his forthcoming report for data.) 
