UPWARD VENTILATION.

A common practice has been to remove the hive cover when the bees are packed for winter and to cover the frames with burlap or some such porous material, the object being to allow the escape of any moisture which may be generated within the hive during the winter. Moisture is being generated constantly as the bees consume the honey stores, but if the bees are adequately packed the amount of moisture will be reduced to the minimum. The chief dancer, of course, is from moisture which condenses, and in an adequately packed hive there is no condensation. The temperature never goes low enough for water vapor to condense. Therefore it is obvious that upward ventilation for the escape of moisture is never needed in hives that are packed as they should be. Any beekeeper who has had trouble in the past with condensed moisture in the hives, or with wet packing over the porous tops, may be sure that he has not provided enough packing material.

Another thing is to be considered in connection with the subject of upward ventilation. The entrances to the hives must be greatly reduced in order that there may not be excessive loss of heat at that point. If upward ventilation is provided, there is opportunity for the wind to blow through even the small entrance, through the hive and out through the porous cover. This current of air will be slight but nevertheless it exists, and serves as an avenue for the escape of considerable heat.

If insufficient packing is provided, upward ventilation becomes almost necessary, unless a large entrance is left. The beekeeper must see to it that he is providing adequate packing material before he gives up the upward ventilation, but he should not count his bees well packed for winter so long as he must provide for the escape of condensed moisture.

THE ENTRANCE.

As has been pointed out, the entrances of hives must be greatly reduced during the winter in order that the efficacy of the bottom packing may be preserved. It is desirable, however, that provision be made for larger entrances during the early fall and again in the spring. To provide conditions suitable at all times while the packing cases are on, the Bureau of Entomology has adopted a type of entrance which to some extent has been used previously in the North. Five ³/₈-inch anger holes are bored in the ends of the packing case at a height that will allow for the thickness of the case floor, the bottom packing, and the thickness of the bottom of the hive. This usually is a little over 6 inches from the lower edge of the case ends. No alighting board should be placed at the outer entrance holes, as it is not needed and serves only to collect snow and ice.

To prevent the tunnels from getting out of alignment at the outer edge, a peg of the diameter of the holes is inserted through the outer hole for each hive and into the tunnel (see [fig. 2]). This peg is usually about 2¹/₂ inches long. This leaves four auger holes, each three-eighths of an inch in diameter, for the bees to use as an entrance during the fall and spring, and during the colder weather a piece of section material or a small board is tacked over three of the holes. (See [fig. 3].) This gives in winter a single hole for an entrance, three-eighths of an inch in diameter. This provides a place for the bees to remove their dead, a place for flight on moderately warm days, and also provides adequate ventilation for the hive while the bees are confined without an opportunity for flight. However, the size of entrance should not be discussed without warning beekeepers that unless adequate packing is provided, such a small entrance may result in the death of the colony. Furthermore, a poorly packed colony will not be able to carry out the bees as they die, and the death rate will be higher; and these things combined may result in an accumulation of dead bees at the entrance, which will serve to suffocate the remaining bees. A colony that is well packed, however, is able to remove all dead bees as fast as they die, and there will never be an accumulation on the floor of the hive. Furthermore, a well-packed colony does not need so large an entrance for ventilation as does one that is not packed or which has not enough packing. If snow drifts over the small entrance here described, the beekeeper need have no anxiety, for the bees can still receive adequate ventilation. If a crust of ice closes the entrance it will be well to break it, but usually the escaping heat will melt this ice before any damage is done.

Fig. 5.—Map of the eastern United States indicating average date of first killing frost in autumn. On this the zones for winter packing are based. No packing is recommended in zones A and B.>

WINTER SCHEDULE.

Great confusion has existed among beekeepers as to the right time to pack the bees for winter, and especially as to the right time to remove the packing in the spring. It is quite possible to give definite directions for both procedures and to place the recommendations on a firm foundation by basing them on weather phenomena. The maps (figs. [5] and [6]), showing the time of the first average killing frost in the fall, serve as a basis for the recommendations for each of the zones into which the map of the eastern United States is divided. Perhaps it will be a matter of surprise to beekeepers in parts of the South to see that, so far as the wintering of the bees is concerned, they are as far north as beekeepers who live many miles farther toward the pole.

The lines on [figure 5] indicate the average dates of the first killing frost in the fall, and these dates, given at the ends of the heavy lines, are of direct value to the beekeeper as giving the proper time for putting on the winter cases. The average dates of the last killing frost in the spring do not show exactly the same lines on the maps, but the differences are not sufficiently great to justify the use of a separate map for this purpose. The authors have chosen therefore to divide the country into the zones indicated, and the recommendations given below apply to each of the zones shown.

On account of the variations in elevation, it is impossible to carry these lines into the Rocky Mountain region, but as packing is just as necessary in the West as in the East, [figure 6] is inserted to indicate roughly the time for the putting on of the packing in the fall. The dates in this map are the average dates of the first killing frost. By consulting Table I the beekeeper of the West may learn the time advised for the removal of the packing, by placing his locality in its proper zone, on the basis of the first killing frost.

Table I.—Dates for the packing and unpacking of been in the various parts of the United States, board on data furnished by the Weather Bureau for the average dates of the first and last killing frosts. The amount of packing recommended for each zone is included.

Zone.	Date for packing.	Date for unpacking.	Packing recommended.[1]	Remarks.
A	.....	.....	.....	None needed.
B	.....	.....	.....	Do.
C	November 25	March 15	2-4- 6
D	November 10	April 10	4-6- 8
E	October 25	May 1	4-6- 8
F	October 1	May 20	4-8-12
G	September 15	June 1	4-8-12	Cellar wintering

[1] In this column the first figure represents in inches the amount of packing needed below the bottom boards, the second the amount of side packing, and the last the amount needed on top.