425 



Since the above was written another theory on the same subject has 

 been propounded by Br. E. G. Love (Jour. N. Y. Micros, Soc, April, 

 1895). Having found the chimneys in soil of "great depth" and "not 

 especially exposed," Br. Love does not agree with Mr. Lander that the 

 larvai, under the influence of unusual heat, come to the surface before 

 tbe 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 Br. Love, " some of the larvce 

 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 j)assage. 

 * * * 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 Br. 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, Br. 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 HORN-FLY TRAP. 



Tlie Manitoba Free Press for November 1, 1894, 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 6 feet high and 4 feet wide, 

 fitting closely in a stable door. On the outer side is hung a curtain, 

 while the 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 oft* the flies, which by a shake of the curtain are sent up 



