31 



I have dissected a great many ful'y matured females, some im- 

 mediately after pairing and others just bef'»re, but have not ob- 

 tained any such results as those tabulated by Professor Landois The 

 greatest number of eggs I have obtained by dissection is 342, and 

 the least number 187. I have also carefully examii ed a series of 

 femal^-s after death, immediately after the eggs had been deposited, 

 to see if any undeveloped eggs were left in the ovaries, and in 

 five cases found they were completely spent, while I found seven 

 eggs each in three others, fourteen in another, and twenty-six in 

 another. This would seem to indicate that the total number of 

 eggs in the ovaries does not represent in all cases the total num- 

 ber that may be laid by a single individual. As stated above, 

 the greatest number of eggs I have yet obtained from a single 

 female is 271 (No. 3), and an examination of the parent insect 

 later showed that the ovaries were spent 



A correspondent of mine in California was asked by me to con- 

 duct a series of experiments in his mill during the month of 

 November, 181)2, to ascertain the exact time required for the in- 

 cubation of the flour- moth eggs, and on December 5 I received 

 the following reply: "The ey:gs hatch in my mill, under the most 

 favorable conditions, in a trifle less than nine days." This is in 

 accordance with my own experiments. Mr. James Fletcher says 

 that caterpillars emerged in December, in a warm olfice, about 

 nineteen days after the eggs were laid. I cannot account for this 

 difference in time, as eggs deposited December 4, 1894, k«pt in 

 my office where the temperature ranged from 38° to 72° Fah. 

 hatched in exactly nine days. As has been shown by Mr. Dauy^z 

 the development of the embryo is greatly retarded by a continuous 

 low temperature, and it is possible that the eggs in Mr. Fletcher's 

 office may have been exposed to a lower temperature than 38° Fah. 

 for a considerable length of time, which would, possibly, explain 

 the difference in the period of development. Another point to be 

 taken into consideration is the fact, that the female is from five 

 to six days in depositing her eggs, and that there is a difference 

 of as many days in the hatching of the first laid and the last-laid 

 eggs of the same generation. 



The active or feeuibg hinge of the larva depends upon the tem- 

 perature of its surroundings, and upon the kind and amount of food. 

 Larv^ hatched from eggs October 9, 1894, were divided into two 

 lots and placed in breeding-cages with wheat flour for food. One 

 cage was placed in the insectary where the temperature varied 

 from 28° to 78° Fah., and the other was kept in a warm office at a 

 temperature of 48° to 82° Fah. Larvae in the former lot were 

 fully matured November 26, or in about seven weeks, and in the 

 latter November 13, or just five weeks from the time they emerged 

 from the eggs. In other experiments conducted to test the tffect 

 of the amount and kind of food on the larvae, I have had varied 

 results. Larvge feeding on coarse corn meal, for example, did not 

 mature as quickly as those in the same room fed on wheat or 

 buckwheat flour. As already stated the average active period of 

 the larva is about forty da>s; but under the most favorable cir- 



