374 p - w - WHITING. 



four; in digestive tract alone, fifty-five; and in genitalia and 

 digestive tract, fifteen. Females deficient in genitalia alone were 

 nine; in digestive tract alone, twenty-two; and in genitalia and 

 digestive tract, nine. 



These figures illustrate the rare occurrence of these abnor- 

 malities in normal stocks. 



Deficiencies in genitalia necessarily entail sterility. Mating 

 reactions are in all cases quite normal. A male having no trace 

 of external genitalia and internal much reduced will mount a 

 female and beat its antennae in the usual manner. Females with 

 reduced genitalia or abdomen swollen and blackened by fecal 

 matter show characteristic responses to caterpillars. Although 

 wasps with deficient digestive tract live only a few days and 

 females lay but few eggs or none it has sometimes been possible to 

 obtain offspring from them. These offspring are usually normal. 



STRAIN SHOWING HEREDITARY DEFICIENCY IN GENITALIA AND 



DIGESTIVE TRACT. 



Hereditary deficiency in genitalia and in digestive tract arose 

 from the combination of material from Lancaster, Pennsylvania, 

 and Iowa City, Iowa. No deficient occurred in the direct line of 

 Iowa City ancestry which included 598 males and 543 females 

 running back to the original female. An I male was crossed to 

 an L female, stock 6. An F 2 male from this cross was mated to 

 an L female, stock 10. This resulted in fifty-three normal males 

 and 130 normal females, besides one female with deficient 

 digestive tract. This is the first occurrence of the character in 

 the ancestry. A sister of this female produced 224 normal males 

 one of which was mated to an I female. Fifty normal males and 

 ninety-six normal females resulted. One of these females pro- 

 duced 139 normal males, five deficient males and one impaternate 

 female. (Female from unfertilized egg from 934-5-) 



Descendents of this impaternate female include in all 209 

 fraternities. Inbreeding was carried on by simply isolating 

 individual females after they had had a chance to mate with their 

 brothers. Ratios of deficients in these fraternities varied er- 

 ratically and a large number of insects died immature. The 

 latter were recorded without reference to sex. 



