RESULTS OF CROSSING EUSCHISTUS VARIOLARIUS 

 AND EUSCHISTUS ICTERICUS WITH REFER- 

 ENCE TO THE INHERITANCE OF TWO 

 EXCLUSIVELY MALE CHARACTERS. 



KATHARINE FOOT AND E. C. STROBELL. 



The two exclusively male characters selected for study in 

 this cross are first, the black or dark brown spot on the male 

 genital segment of Euschistus variolarius and, second, the intro- 

 mittent organ, which differs markedly in length in the two 

 species. 



In two recent papers 1 we described in detail the transmission 

 of the above-mentioned exclusively male characters in a cross 

 between Euschistus variolarius and E. servus and the results 

 from the study of the transmission of these two characters in the 

 cross of E. variolarius with E. ictericus are merely a confirma- 

 tion of the results obtained from the cross of E. variolarius 

 with E. servus. The results from the latter cross were pub- 

 lished first because they were more satisfactory, for the reason 

 that the spot which is so pronounced on the male genital seg- 

 ment of variolarius is entirely absent from the male segment of 

 E. servus, whereas it is not entirely absent from the genital seg- 

 ment of E. ictericus. Although ictericus is described as having 

 no spot on the*genital segment, a faint spot is frequently present. 

 This is not easily determined until the segment is pulled out and 

 closely examined, but the spot, if present, can then be clearly 

 seen, though it is not nearly so pronounced as that of variolarius. 

 (Compare photos 61 and 62.) Although this spot is not a 

 constant feature in ictericus, it is present often enough to make 

 it impossible to determine how much of the inheritance of the 



1 "Results of Crossing Euschistus variolarius and Euschistus servus with Refer- 

 ence to the Inheritance of an Exclusively Male Character," Journ. Linn. Soc. 

 London, Zool., Vol. XXXII, 1914. 



"Results of Crossing Two Hemipterous Species, with Reference to the In* 

 heritance of Two Exclusively Male Characters," Journ. Linn. Soc. London, Zool., 

 Vol. XXXII, 1915. 



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