425 
SiDce the above was written another theory on the same subject Las 
been propounded by Dr. E. G. Love (Jour. X. Y. Micros. Soc, April, 
1895). Having found the chimneys in soil of u great depth" and "not 
especially exposed," Dr. Love does not agree with Mr. Lander that the 
larva?, under the influence of unusual heat, come to the surface before 
rbe proper time for their final transformation, and construct these huts 
as a protection against too great heat and possible enemies. He thinks 
that pupal changes may be in progress during a portion of the time 
the insect is making its way to the surface. The time required for the 
larva? to reach the surface would vary, of course, with the depth from 
which they started, the nature of the soil tunneled, and the directness 
of the line followed. " In any case," says Dr. Love, " some of the larva? 
would miscalculate the time required, and reach the surface before 
they were prepared to assume the imago condition, and this number 
would be greater when the conditions united to favor a short passage. 
* * * Thus it is that the insects sometimes find themselves exposed 
to the upper air before the proper time for their final transformation, 
and are compelled to seek some temporary shelter. This is often found 
under sticks or stones which may be near, but more frequently they 
construct the huts as extensions of the tunnels." 
It will be seen that Dr. Love practically agrees with Mr. Lander in 
considering the chimneys places of temporary shelter while the insect is 
undergoing its final transformation. But, while Mr. Lander thinks the 
larva is stirred to activity by unusual warmth. Dr. Love thinks that, 
at the expiration of the seventeen years, it is prompted by a natural 
instinct to seek the surface : a journey the length of which it has no 
power of calculating, and hence sometimes reaches the surface of the 
ground prematurely. For protection it then simply extends its burrow 
in the form of a chimney. 
A HOBN-FLY TRAP. 
The Manitoba Free Press for November 1, 1891. gives a short descrip- 
tion of a fly-trap for use against the horn fly, which is so ingenious and 
so simple that it deserves to be made known more widely. 
The device is described as a structure G feet high and 4 feet wide, 
fitting closely in a stable door. On the outer side is hung a curtain, 
while tbe inner side, next to the doorway, is composed of broom corn 
extending from the top downward and from each side toward the cen- 
ter, so that the cow in going through is brushed over every part of the 
body, while the elastic broom corn, springing back into place, pre- 
vents the flies from following her into the stable. The roof of the struc- 
ture is of wire netting, in which is a trap which the flies can enter but 
can not leave. In use the cow is driven into the pen, the curtain let 
down behind her, and as she passes into the stable the broom-corn 
brush sweeps off the flies, which by a shake of the curtain are sent up 
