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lated for the purpose of these observations were seen to emerge from 

 their pupa cases, and consequently there was no possibility of their 

 having been fertilized. The plants upon which these females were 

 kept were growing in small pots covered with lantern chimneys, 

 which were closed at the top with cheese cloth. Four trials were 

 made: 



i. April 3, 1902, an unfertilized female began egg laying, and 

 on April 17 three eggs were observed to have hatched. 



2. April 17, 2902, an unfertilized female began egg laying, and 

 on April 29 several eggs had hatched. 



3. Dec. 8, 1902, a female emerged, was isolated on a tomato 

 plant, and began egg laying Dec. 12 (females usually begin egg lay- 

 ing on the second or third day after emergence), and continued, 

 averaging four per day for eleven days. Personal observations were 

 here discontinued, but E. A. Back, an undergraduate student at the 

 Entomological Laboratory, noted that the adult died Jan. 1, 1903. 

 On Jan. 7 I found the plant dead, apparently from cold, and on ex- 

 amination of the leaves I found that about three-fourths of the eggs 

 had hatched, and that some of -the larvae were in the second instar at 

 the time the plant died. Quite a number of eggs were found that 

 had certainly been laid during my absence, but they were not 

 counted. 



4. March 17, 1903, a female emerged from its pupa case, and 

 was isolated on tomato and chickweed growing in the same pot. 

 Egg laying began March 18. Eggs were deposited on the stems and 

 upper and lower surfaces of the leaves of both plants, making it im- 

 possible to count from day to day all the eggs that had been laid. 

 On April 2, forty-nine eggs were counted, and on April 22 eighty more 

 were known to have been added to this number. There were about 

 eight days altogether when the female was in such a position on the 

 plant that no attempt was made to count the eggs for fear of dis- 

 turbing her. At a very low estimate, twenty- five eggs were laid dur- 

 ing these days, The offspring of this female began to emerge as 

 adults on April 22, and the original female was transferred to a 

 chickweed plant growing in another pot. By an accident I lost on 

 the same day the positive identity of this insect, but I am quite sure 

 that she produced the forty-nine eggs which I counted on April 29, 

 after which observations on this insect were discontinued. So far as 



