THE STATE ENTOMOLOGIST. 93 



taiiied most importance — an area of about 240 square miles around Yoka- 

 homa. As I am informed hy a fellow-entomologist, who lias resided there 

 for many j^ears, and, in an official capacity, has made minute and daily me- 

 teorological observations, the winters are less severe than with us, the snow 

 seldom remaining on the ground more than an hour : the summers are like- 

 wise less hot ; but the climate during the rearing season is quite similar to 

 that of our southern counties during the same period, though with fewer 

 -sudden changes. The mean annual temperature is 63.50 F. and the solar 

 radiation 18.55. The wettest months are April and June, the average rain 

 fall in April being 10.5 in May 5.1 and in June 12.4 inches. The rains stop 

 suddenly in June, when feeding commences. The temperature of the four 

 months of April, May, June and July averages as follows : April, maximum 

 70^ minimum 52°; Ma}", maxm. 67°, minm. 56° ; June, maxm. 74°, minm. 

 66"; Juh", maxm. 80°, minm. 72°. Thus their feeding months — parts of 

 June and July — do not compare unfavorably with ours — parts of April 

 and May. 



We have already seen the importance of getting healthy eggs, free from 

 hereditary' disease, and of good and valuable races. Eggs keep best during 

 the winter at a temperature of 40° F., and should be placed in zinc or tin 

 boxes where no mice or other animals can reach them, and where the at- 

 mosphere is not too moist. The temperature may be decreased and m&y 

 even sink below freezing j^oint, without injury; but ^hould never be al- 

 lowed to rise above the 40°. Great care should especially be taken to 

 prevent a too early incubation in the spring. Mulberry leaves start to grow 

 quite late, and unless the eggs are kept back by being placed in some room 

 or cellar that is cooler than the atmosphere, our earl}' warm April days will 

 cause them to hatch before there ai-e any leaves for the young worms to feed 

 on. The hatching may be indefinitely delayed providing the eggs are kept 

 iit a temperature below 40° F.; for in France it is often deferred by carry- 

 ing eggs up in the mountains until the second crop of mulberry leaves can 

 be used. 



As soon as the mulberry leaves commence to put forth, the eggs may be 

 brought out and they Avill then very soon hatch by the natural heat of the 

 season ; though if the weather be changeable, it is best to regulate the tem- 

 perature by means of fires^ commencing at about 75° F. and increasing it 

 about 2° per day until it reaches 85°, when the worms will begin to hatch. 

 By no means must the eggs be exposed to the sun's rays, which would scorch 

 them in a very short time; and even in the shade, as the temperature is 

 raised and the hatching period approaches, the atmosphere should be kept 

 more and more moist, either by sprinkling the floor or by other means. 

 The worms will thus eat through their egg shells more easily and be more 

 fresh and vigorous. 



Any room with a northeastern exposure, and which can be well and 

 thoroughly ventilated will answer for the rearing of the worms. An open 

 fire-place is always desirable, as in cold, damp weather, the room may be 

 rendered comfortable and at the same time purified by the draft which the 



