A NEW SPECIES OF TOXOPTEHA. 



13 



From this table it will be soon that there were 14 generations of 

 the first-born series and 7 of the last born. This would give a])pr()xi- 

 mately 10 j generations for the year. 



MOLTING. 



In 1009 some molting exjieriments wore conducted. Five indi- 

 viduals that had just been born were placed in a specially ])repare(l 

 cage, as shown in figure 7, and observed throughout the molting 

 periotl. After becoming atlult it was found that there were 1 male 

 and 1 oviparous and 3 viviparous females among these 5 individuals. 

 In 1910 observations were also made on a stem-mother to note the 

 number of molts. Of the 6 individuals, 

 all molted 4 times without exception. 



FECUNDITY OF THE SUMMER FORMS. 



The 19 individuals concerned in the 

 generation series produced 311 young, or 

 an average of 16.3 young each. The max- 

 imum number of young produced by a 

 single individual was 35. The maximum 

 number of young produced by any indi- 

 vidual in a single day was 5, 



AGE WHEN INDIVIDUALS BEGIN REPRO- 

 DUCING. 



The period between birth and reproduc- 

 tion varies greatly, being longest in the 

 spring, when it varies from 15 to 22 days. 

 In summer the shortest period was 6 days, 

 varying from 6 to 1 3 days. In the fall it va- 

 ries from 9 to 13 days. The average period 

 throughout the season for the 13 individ- 

 uals of the series of first born is 13.1 davs. 



Fig. iS.- Toxoptcra muhhnbcrgise: 

 Eggs deposited in curled leaf sheath- 

 Greatlj' enlarged. (Original.) 



LENGTH OF LIFE OF THE VIVIPAROUS FORMS. 



The length of life, like the period between birth ami reproduction, 

 varies greatly. During the spring, when lower temperatures prevail. 

 the viviparous forms will live from 30 to 63 days, while in the summer 

 they live from 16 to 29 days, and in the fall over 30 days. The 

 average length of life throughout the season for the 13 viviparous 

 individuals of the series of first l)orn is 28.9 days. 



THE SEXES. 



The sexes make their appearance about the lirst week in October. 

 There does not appear to ])e any particular generation that consists 



