P. W. WHITING. 



results of such summarizing for this group. It may be noted 

 that tendency toward production of deficiency is relatively low 

 when mothers are young but increases up to the tenth to four- 

 teenth day when it rapidly falls. Essentially the same form of 

 curve is seen for deficient males, deficient females, and immature 

 deaths but data for females are rather meager. 



The various types of deficients as they occurred in the different 

 bottles are recorded in Table B. 



By glancing at the percentages in this table it may be seen that 

 there is no consistent and significant change in ratio of any type 

 of deficiency according to the age of the mother. The continuous 

 increase in females with deficient digestive tract is not to regarded 

 as significant because of small numbers. 



Crosses of Deficient and Normal Stocks. 



All females of the deficient line were lost through their failure 

 to produce daughters. Their sons were crossed with normal L 

 stocks. Daughters were back-crossed to the same males for 

 three generations. Although the males came from the selected 

 material and were used as parents for four successive generations, 

 the ratio of deficient did not exceed two per cent. 6,954 wasps of 

 the third generation were bred. Wasps were deficient in geni- 

 talia alone, ninety-six; in digestive tract alone, twenty; in 

 genitalia and digestive tract, fourteen. 



A male from the selected deficient line was crossed to a female 

 from Iowa City stock 1 1 . The male had orange eyes, wrinkled 

 wings, defective r 4 vein, and yellow mesosternum. Stock 11 is 

 characterized by black eyes, flat wings, normal r 4 vein and sooty 

 mesosternum. Orange acts as a unit with no overlapping, 

 wrinkled has but little. Defective and sooty are variable 

 multiple factor characters in this cross. 



The deficient in F 2 numbered among 2,252 males only thirty- 

 five or 1.55 per cent., and among 957 females only five or 0.52 

 per cent. 



The thirty-five males included nineteen orange, fifteen wrinkled, 

 and twenty sooty. Among the twenty in which venation could 

 be determined ten had defective r 4 . There is thus no association 

 between deficiency and the characters mentioned. 



