. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CROSSING TWO HEMIPTEROUS SPECIES. 229 sex. This would place sex-linked factors for the testes in the X- chromosome of these insects; and locating these factors in this chromosome would involve their being in the female-producing spermatozoa only, and this type of spermatozoa therefore would carry the determining factors for both the ovaries and the testes, while the male-producing spermatozoa would carry neither the one nor the other. We shall try to show by an analysis of the chromosomes that it is as impossible to associat
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CROSSING TWO HEMIPTEROUS SPECIES. 229 sex. This would place sex-linked factors for the testes in the X- chromosome of these insects; and locating these factors in this chromosome would involve their being in the female-producing spermatozoa only, and this type of spermatozoa therefore would carry the determining factors for both the ovaries and the testes, while the male-producing spermatozoa would carry neither the one nor the other. We shall try to show by an analysis of the chromosomes that it is as impossible to associate the testes with the sex-chromosomes as we have shown by experiment is true for the two other exclusively male characters—the genital spot and the intromittent organ. In order to simplify the dis- cussion, we reproduce the following diagram used in an earlier paper to show the method of division of the 14 somatic chromo- somes which are distinctive of both E. variolarius and E. servus. In the diagram we have used the method of designating uni- valents by the letters of the alphabet, bivalents being represented by AB, CD. EF. Sp. Tid. Second Sp. Cyte Chromosomes. Chromosomes. A C E X - 9 First Sp. Cyte Chromosomes. ^~A C E Y cf A B C D E F X Y B D F X 9 D F Y C? Scheme of the two maturation divisions of Euschistus variolarius and Euschistus servus based on the assumption that the first maturation division separates auto- somes of maternal and paternal origin and the second division halves .them. The .XTF-chromosomes on the contrary being halved in the first division and separated in the second division. The relative positions of the autosomes may be changed unless definite chromosomes are always destined to the same pole, but reversing their position in this regard does not alter the end result—that the only chromosome common to both so-called male-producing spermatids is the The above diagram demonstrates the two types of spermatozoa, those having the X-chro
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
