XIY 
We have also to notice the somewhat threatening prevalence 
in the rapidly developing orchard region of Southern Illinois, 
of the cankerworm and the oystes shell bark louse, both 
insects likely to cause great trouble to those not thoroughly 
well acquainted with them and with modern methods of pre¬ 
vention and defence against them. 
The experimental work of the office has been greatly facili¬ 
tated, and rendered far more accurate and profitable by the new 
iusectariurn, or experimental entomological laboratory, provided 
for by the Legislature at its last session. It has been in con¬ 
stant and extensive use from the date when it was ready for 
occupancy. 
The important part of this insectarium is essentially a con¬ 
servator fifteen feet by thirty, standing entirely above ground, 
with glass roof and brick walls, with the exception of the end 
wall, which is glass above the level of the sides. The building 
stands north and south, opening to the south with double doors, 
one of glass and one of wire gauze. The roof is covered by four 
rows of sash all hinged at the ends in such a way that the sash 
of the lower row can be lifted at the lower end, while the sash 
of the upper row may be opened widely at the peak of the roof. 
The glass on the lower row of sash upon each side is deadened 
with'white paint (that of the upper row being left clear), and 
the admission of sunlight is further controlled by a screen of 
cheese cloth sliding on wires extending along the entire middle 
of the room beneath the two central rows of sash. The upper 
sash are opened and closed by a ventilating apparatus which 
moves all together, while the lower are conveniently raised by 
hand. The room is divided into two apartments connected 
with double doors, one of which is provided with hot-water 
pipes supplied by a furnace in a cellar adjoining. Water is of 
course laid on with hose-pipe arrangements for its convenient 
distribution. 
With these arrangements it was easy to keep the temperature 
within one or two degrees, above or below, that of the outer 
air, whatever the weather might be. The interior is furnished 
with tables in benches, work-tables, etc., for breeding-cage and 
root-cage work, and contains a brick-lined trench three feet wide 
and fifteen feet long by three feet deep, cemented within and 
filled with earth, for the larger plants and for small plot experi¬ 
ments. 
An enclosed piece of ground adjoining this insectarium has 
given us ample opportunity for out-door experiments, made 
parallel with those within, and serving as a perfect check on the 
insectarium work. Our most important experiments were made 
in this plot and in the trench within the insectarium, where the 
conditions were, as will be seen, very different from those of an 
ordinary breeding cage. They were really small plot experiments 
under perfect control. 
