Ailanthiculture. 203 
These cylinders are constructed of the cheapest ordinary perfo- 
rated zinc, and are formed by soldering one end to the other of 
previously measured lengths, so cut in sizes as to form when 
soldered cylinders of different diameters, thereby enabling one 
_ cylinder to slip inside another. One end is left open, the other is 
covered with gauze or canvass; to each cylinder belongs a round 
or square top of a little larger size, made of elm or deal. 
Height. Diameter. 
Dimensions of cylinders, 103 inches x 8# inches. 
” 9 11 ” x 9 ? 
99 99 1 rg ” x 9 » 93 
fi Ms Roe a Eon ae gO 
Cylinders of equal diameter but less height (8 inches diameter 
x 4 inches high) are useful for placing the insects in when newly 
born. They may be held by their wings if developed, or by the 
shoulders if otherwise; the males are placed in one cylinder, the 
females in another, to the number of 8 or 10 in each; a glance will 
tell the initiated which are the sexes, and towards night it is easy 
to adjust- the numbers, so that an equal number of males and of 
females may be introduced into one of the larger cylinders, and 
the wooden lid placed on it: this is then carefully put away in a 
quiet place. If looked at in the morning, it will be found that the 
pairs are united; this will happen as the rule, but in some cases, 
either from a sudden falling of the temperature, or if some of the 
insects are not quite ready for coition, or have been developed 
rather late in the evening, they do not pair. If so, carefully re- 
move the wooden lid, take out those that have not paired, and 
leave behind those in copulation, which will remain quiescent till 
dusk. When they separate, the female instantly, as if there was 
no time to lose, begins to lay her eggs. Those not paired will 
probably do so the following night. After coition has ceased, the 
males should be let go if not required for other purposes: M. 
Méneville gives them to his chickens. 
A male will serve more than one female successfully, as I have 
proved by an experiment below quoted. It is curious also that, 
even if no impregnation takes place for want of a male or other- 
wise, eggs are deposited by the female the third or fourth night 
after exit; hence coition ought normally to take place on the first 
or second night after exit: and further I have observed, that if the 
male happens to remain without coition for two or more nights, it 
is very doubtful whether, even if he should have access to a fresh 
female, coition will ensue. Coition must, therefore, in both sexes 
Pz 
