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Sfilim on Dimorphism of Spermatozoa
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OF ILLINOIS
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STUDIES ON DIMORPHISM OF SPERMATOZOA
BY
CHARLES TIMOTHY SENAY
B.S. Trinity College, 1914
THESIS
Submitted in Partial Fulfillment of the Requirements for the
Degree of
MASTER OF ARTS
IN ZOOLOGY
IN
THE GRADUATE SCHOOL
OF THE
UNIVERSITY OF ILLINOIS
1915
UNIVERSITY OF ILLINOIS
THE GRADUATE SCHOOL
„_,..;W8,y 5.1 191 5
I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPER-
\TsioN BY cijyyi3Li:s tlMQlM..3MAY.*. „
ENTITLED SIL'2IES....01l-..LIlIGHPiiim...DE....SP.])IB]^.GZDA«
BE ACCEPTED AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE
DEGREE OF IIAST}i:R....OS....ARlS.. „
Recommendation concurred in :*
Committee
on
Final Examination*
^Required for doctor's degree but not for master's.
UlUC
STUDIES ON DIMORPHISM OF SPERMATOZOA
Contents
I. INTRODUCTION ^^S®
1. Object of Research 1
2. Theoretical Basia 1
3. Listed Species having Sex Chromosomes 2
4. Previous Work on Size Dimorphism 15
II. MATERIAL AND METHODS
1. Most Desirable Species 15
2. Fixation and Staining 16
3. Method of Measurement 17
4. Sources of Error 17
III. DATA
Heraiptera
1. Leptoooria trivittatus 21
2. Reduviolus ferus 21
3. Corizua lateralus 22
4. Euschistus variolarius 22
5. Cosmopepla carnifex 24
Coleoptera
6. Passalus cornutus 24
7. Berosus striatus 25
Annelida
8. Heliodrilus caliginosa 25
IV. DISCUSSION 26
Acknowledgments 29
V. SUMJ/IARY 31
VI., BIBLIOGRAPHY OF SPERMATOGENESIS 33
31SS20
I. INTRODUCTION
Obj ect of Resear ch
A limited number of caaes of size dimorphism of spermato-
zoa has been reported. It is desirable to see if size dimorphism
is a general phenomenon. Therefore the included piece of research
was undertaken in the aim of determining if there was size dimor-
phism of spermatozoa from normal adult individuals of species
hitherto unstudied.
3. Theoreti cal Basis
Numerous investigators have directed their attention to
the problems of spermatogenesis and oogenesis as they manifest them
selves in the various groups of animals. As a result of their
investigations a vast amount of data has been accumulated, the
large majority of which indicates that there are two kinds of
spermatids in practically all species, differing quantitatively in
chromatin content. This chromosomal difference proclaims itself
in two ways; as the familiar unpaired "x" chromosome and as the
unequal "x, y" pair of chromosomes. Modifications of these main
types are found and usually arise by division of the "sex" chromo-
some, into more numerous units. Examples of all these variations
will be found in an included list.
If, as the above evidence indicates, the chromatin con-
tent of the primitive germ cell is unequally divided in the sperma-
tids and this division is constant within a given species, then
there should be spermatozoa of two lengths in the male sexual
product. Since each of these spermatozoa will be the mean of a
Gaussian variation curve, a number of other lengths will be found.
3-
A graph of the obtained results should be a combination of two
normal variation curves, with two high points, indicating the two
means. In cases where there has been no observed difference in the
spermatids or where the female gametes possess the unequal chrom-
atin distribution, a simple variation curve might be obtained.
In the following data "n" indicates the somatic number
of aatoeomes. "x"^ or "x" and "y" indicate the sex chromosomes.
3' Lis ted Species haying Sex Chrqmo s ome s
TYPE I. n/2, n/2 + x.
Amphibia
Alytes obstetricians. *M. = 16. **F. = 16 + x.
Janssens, F. A. P. & Willems, J. 1908.
Arachnida
Epeira sclopetaria. M. = 11. F. = 11 + x.
Berry, E. H. 1906.
Coleoptera
Anomoglossus emarginatus. M. = a. F. = a + x.
Stevens, N. M, 1906.
Chrysomela sirailis. M. = 11. F, = 11 + x.
Stevens, N. M. 1909.
Diabrotica. 12-punctata. M. = 9. F. = 9 + x.
Stevens, N. M. 1908a.
Diabrotica soror. M. = 9. F. - 9 + x.
Stevens, N. M. 1908a.
Diabrotica vittata. M. = 10. F. = 10 + x.
Stevens, N, M. 1908a.
Elater sp. M. = 9. F. = 9 + x.
Stevens, N. M. 1906.
Ellychnia corrusca. M. = 9. F. = 9 + x.
Stevens, N. M. 1909.
Hydrophilus piceus. M. = 15. F. = 15 + x.
Arnold, G. 1909.
Limoneus griseus. M. = 8. F. = 8 + x,
Stevens, N. M. 1909.
Necrophorus sayi. M. = 6. F. = 6 + x.
Stevens, N. M. 1909.
Phctinus consanguineus. M, = 9. F. = 9 + x.
Stevens, N. M. 1909.
Photinus pennsylvanicus. M. = 9. F. « 9 + x.
Stevens, N. M. 1909.
Stenopelmatus. M, = 23. F. = 23 + x.
^ Stevens, N. M. 1909.
M = male determining
**F = female determining
-3-
Corrodentia
Ceraatipeocue venosus. M. = 8. F. = 8 + x.
Boring, A. M. 1913.
Echinodermata
Hipponde eeculenta. M. = a. F. = a + x,
Tennent, D. H. 1911.
Toxopneustes variegatue. M. = a. F. = a + x.
Tennent, D. H. 1913.
Hemiptera
Agallia sanguinolenta. M. = 10. F. = 10 + x.
Boring, A. M. 1907.
Alydus eurinus. M. = 6, F. = 6 + x.
Montgomery, T. H, 1906.
Alydus piiosulus, M. = 6. F. = 6 + x.
Wilson, E. B. 1905, b & c, 1906.
Amphiscepa bivittata. M. = 13. F. = 13 + x.
Boring, A. M. 1907.
Anasa armigera. M. = 10. F. = 10 + x.
Montgomery, T. H. 1906.
Anasa sp. M. = 10. F. = 10 + x.
Montgomery, T. H. 1906.
Anasa tristis. M. = 10. F. = 10 + x.
Wilson, E. B. 1905, b & c, 1906, 1907a.
Aphrophora 4 notata. M. = 13. F. = 13 + x.
Boring, A. M. 1907.
Aphrophora quadrangular! s. M. = 11. F. = 11 + x.
Stevens. N. M. 1906.
Aphrophora spumaria. M, = 11. F. = 11 + x.
Boring, A. M. 1907.
Archimerus calcarator. M. = 7. F. = 7 + x.
Wilson, E. B. 1905.
Atymna castanea. M. = 10. F. = 10 + x.
Boring, A. M. 1907.
Campylenchia ourvata. M. = 9. F. = 9 + x.
Boring, A. M. 1907.
Catorintha. M. = 13. F. = 13 + x.
Wilson, E. B. 1907.
Ceresa bubalus. M. = 10. F. = 10 + x.
Boring, A. M. 1907.
Ceresa diceros. M. = 10, F. = 10 + x.
Boring, A. M. 1907.
Ceresa taurina. M. = 10. F. = 10 + x.
Boring, A. M. 1907.
Chariesterus antennator. M. = 13. F, = 13 + x.
Wilson, E. B. 1909.
Chelinidea. M. = 10. F. = 10 + x.
Wilson, E. B. 1907. Morrill, C. V. 1910.
Chlorotettrix unicolor. M. = 8. F. = 8 + x.
Boring, A. M. 1907.
Chlorotetrix vividus. M. = 10. F. = 10 + x.
Boring, A. M. 1907.
Cicada tibicen. M. = 13. F. = 13 + x.
Wilcox. 1895.
-4-
Hemiptera
Claetoptera obtusa. M. = 7. F. * 7 + x.
Boring. A. M. 1907.
Corizus alternatuB. M. = 6. F. = 6 + x.
Montgomery, T. H. 1906.
Corizus lateralus. M. = 6. F. = 6 + x.
Montgomery, T. H. 1906.
Corynoooris diatinctus. M. = 13. F. 13 + x.
Wilson, E. B. 1909.
Diedrocephala coccinea. M. = 11. F. * 11 + x.
Boring, A. M. 1907.
Diedrocephala mollipes. M. = 11. F. = 11 + x.
Boring, A. M, 1907.
Enchenopa binotata, M. = 9. F, = 9 + x.
Boring, A. M. 1907.
Entila sinuata. M. = 10. F. = 10 + x.
Boring, A. M. 1907.
Euthoctha galeator. M. = 10, F. = 10 + x.
Wilson, E. B. 1907.
Karmostes reflexulus. M. = 6. F. = 6 + x.
Montgomery, T. H. 1901, 1906.
Hygotrechus sp. M. * 10. F. = 10 + x.
Montgomery, T. H. 1906.
Largus cinctus. M. = 5. F. = 5 + x.
Wilson, E. B. 1907, 1909, 1913.
Largus sucoinctus. M. = 6. F. = 6 + x.
Wilson, E, B. 1907.
Leptocoris trivittatus. M. = 6. F. = 6 + x.
Wilson, E. B. 1907.
Leptoglossus phyllopus. M. = 10. F. = 10 + x.
Wilson, E. B. 1907,
Limotreohus marginatus. M. = 10. F. = 10 + x.
Montgomery, T. H. 1906.
Lygus pratensis. M. = 17. F. = 17 + x.
Montgomery, T. H. 1906.
Margus inconspicuus. M. = 11. F. = 11 + x.
Wilson, E. B. 1907.
Narnia. M. = 10. F. = 10 + x.
Wilson, E. B. 1907.
Oedencala dorsalis. M. = 6. F. = 6 + x.
Montgomery, T. H, 1906.
Pachylis gigas. M. = 7. F. = 7 + x.
Wilson, E. B. 1907.
Philoenus spumarius. M. - 11. F. = 11 + x.
Boring, A. M. 1907.
Phlepsius irrotatue. M. = 7. F. = 7 + x.
Boring, A. M. 1907.
Phymata sp. M, = 14. F. = 14 + x.
Montgomery, T. H. 1906.
Poeciloptera bivittata. M. = 13. F. = 13 + x.
Boring, A. M. 1907.
Poeciloptera pruinosa, M. = 13. F. = 13 + x.
Boring, A. M. 1907.
-5-
Hemiptera
Poeciloptera eeptentrionalis. M. = 13. F. = 13 + x.
Boring, A. M. 1907.
Protenor belfragi. M. = 6. F. = 6 + x.
Montgomery, T, H. 1901, 1906.
Pyrrochoris apteris. M. = 11. F. = 11 + x.
Henking, H. 1891. Wilson, E. B. 1907.
Vanduzea arcuata. M. = 8. F. = 8 + x.
Boring, A. M. 1907.
Myriapoda
Lithobius ep. M. = a. F. = a + x,
Elackman. 1907.
Scolopendra heros. M. = 16. F. = 16 + x.
Elackman, M. W. 1905, 1910.
Scolopendra subspinipee. M. = 16. F. = 16 + x.
Elackman, M. W. 1905, 1907.
Scutigera forceps. M. = 18. F. = 18 + x.
Medes, G. 1905.
Nematoda
Ancyracanthus cystidicola. M. = 5. F. = 5 + x.
Mulson, K, 1912.
Ascaris megalocsphala. M. = a. F. = a + x.
Edwards. 1910.
Creseis aclcula, M. = 9. F. = 9 + x.
Zarnik, B, 1913.
Heterakis dispar. M. = 4. F. = 4 + x.
Gulick, A. 1911.
Heterakis inflexa. M. = 4, F. = 4 + x.
Gulick, A. 1911.
Heterakis vesicularis. M. = 4. F. = 4 + x.
Gulick, A. 1911.
Strongylus paradoxus. M. = 5. F. = 5 + x.
Gulick, A, 1911.
Strongylus tenuis. M. = 5. F. = 5 + x.
Gulick, A. 1911.
Odonata
Anax Junius. M. = 13. F. = 13 + x.
Lefevre, G. & McGill, C. 1908.
Orthoptera
Anabrus sp. M. = 16. F. = 16 + x,
McClung, C. E. 1903.
Aplopus mayeri. M. = 17. F. = 17 + x.
Jordan, H. E. 1908.
Arphia simplex. M. = 11. F. = 11 + x.
Carothers, E. 1913.
Arphia tenebrosa. M. = 11. F. = 11 + x.
Davis, H. 8. 1908.
Blatta germanica. M. = 11. F. = 11 + x.
Morse, M. 1909.
-6-
Orthoptera
Blatta gerraanica. M. = 11. F. = 11 + x.
Stevens, N. M. 1906,
Brachyatola magna. M. = 11. F. = 11 + x.
Sutton, W. S. 1900.
Ceuthophilua ep. M. = 18. F. = 18 + x.
Stevens, N. M. 1912,
Chortophaga viridifasciata, M. = 11. F. = 11 + x.
Davis, H. S. 1908,
Chrysochjaon dispar. M. = a. F. = a + x.
Veaely, J. 1913.
Deoticus verrucosus. M. = 15. F. = 15 + x.
Buchner, P. 1907.
Diestraramena marmorata. M, = 28. F. = 28 + x.
Schellenberg, A. 1913.
Dissosteira Carolina. M. = 11. F. = 11 + x.
Davis, H. S. 1908. Carothers, E. 1913.
Gryllus assirailis. M. = 14. F. = 14 + x.
Baumgartner, W. J.
Gryllus campestris. M. = 19. F. = 19 + x.
Buchner, P. 1909.
Gryllus domesticus. M. = 10. F. = 10 + x.
Baumgartner, W. J. 1904.
Gryllotalpa borealis. M. = 11. F. = 11 + x.
Payne, F. 1912,
Gryllotalpa vulgaris. M, = 11. F. = 11 + x.
Vom Rath. 1892.
Hesperotettix prattensis. M. = 11, F. = 11 + x,
McClung, C. E. 1905.
Hesperotettix speciosus. M. = 11. F, = 11 + x,
McClung, C, E. 1905.
Hesperotettix viridis. M. = 11. F. = 11 + x.
McClung, C. E. 1905.
Hippiscus phoeniooptenis. M. « 11, F. = 11 + x.
McClung, C. E. 1900.
Hippiscus sp, M. = 11. F. = 11 + x.
Buchner, P. 1909.
Hippiscus tuberculatus. M. = 11, F. = 11 + x.
Davis, H. S. 1908.
Leptynia attenuata. M. = 17. F. = 17 + x,
de Sinety. 1901.
Leucophaea maderiae. M. = 11. F. = 11 + x,
Morse, M. 1909.
Locusta viridissima. M. = 16. F, = 16 + x.
Otte, H. 1906.
MelanopluB bivittatus. M, = 11, F. = 11 + x.
Nowlin, N, 1908.
Melanoplus feraoratus. M. = 11, F. = 11 + x.
Davis, H. S. 1908.
Melanoplus, femur rubrum. M. = 11. F. = 11 + x.
Wilcox, E. V. 1895,
Merrairia bivittata. M, = 11. F. = 11 + x.
McClung, C. E. 1905.
-7-
Orthoptera
MicDcentra ep. M. = 16. F. = 16 + x.
McClung, C. E. 1908.
Oedipoda. F. - 11. F. «= H + x.
Buchner, P. 1909.
Oedipoda miniata. M. = a. F. = a + x.
de Sinety, R. 1901.
Orcheeticus sp. M, = 16. F. = 16 + x.
McClung, C. E. 1902.
Orphania denticauda. M. = 15. F. = 15 + x.
de Sinety, R. 1901.
Psunphagus marmoratus. M. = 9. F. = 9 + x.
Giglio, Tos. 1908.
Periplanata americana. M. = 11. F. = 11 + x.
Morse, M. 1909.
Pezotettix. M. = 11. F. = 11 + x.
Buchner, P. 1909.
Phrynotettix raagnus. M. = 11, F. = 11 + x.
Pinney, E. 1908.
Psophua. M. = 11. F. = 11 + x.
Buchner, P. 1909.
Schistocerca alutacca. M. = 11. F. = 11 + x.
Hartman, F. 1913.
Schistocerca americana. M. = 11. F. = 11 + x.
Hartman, F. 1913a.
Scudderia sp. M. = 16. F. = 16 + x.
McClung, C. E. 1902.
Steiroxys trilineata. M. = 14. F. = 14 + x.
Davis, H. S. 1908.
Stenobothrus biguttulus. M. = 8. F. = 8 + x.
Gerard, Pol. 1909.
Stenobothrus curtipennis. M. = 8. F. = 8 + x.
Davis, H. S. 1908.
Stenobothrus parallelua. M. = 8. F. = 8 + x.
de Sinety, R. 1901.
Stenobothrus viridulus. M. = a. F. = a + x.
Meek, C. F. U. 1911 & 1912.
Stenopelmatus. M. = 23. F. = 23 + x.
Stevens, N. M. 1905,
Stylopyga orientalis. M. = 11. F. = 11 + x.
Morse, M. 1909.
Syrbula acuticornis. M. = 11. F. = 11 + x.
Robertson. 1908.
Syrbula admirabilis. M. = 11. F. = 11 + x.
Robertson, W. R. B. 1908.
Syrbula fusca vittata. M. = 11. F. = 11 + x.
Robertson, W. R. B. 1908.
Xiphidiura fasciat\im. M. = 16. F. = 16 + x.
McClung, C. E. 1902.
Vertebrata
Didelphys virginiana (opossum). M. = 8. F. = 8 + x
Jordan, H. E. 1911.
-8-
TYPE II. n/2 + y, n/S + x
Annelida
Tomopteris oniscif ormis. M. = 8 + y. F. = 8 + x.
Shreiner, A. & K. E. 1906.
Zoogonus mirus. M, = 4 + y. F. = 4 + x.
Goldschmidt, R. 1905.
Araohnida
Lyoosa insopita. M. » 12 + y. F. = 13 + x.
Montgomery, T. H. 1905.
Coleoptera
Adalia blpunctata. M. = 9 + y. F. = 9 + x.
Stevens, N. M. 1909.
Blepharida rhois. M. = 15 + y. F. = 15 + x.
Stevens, N. M. 1906.
Buprestidae. M. = a + y. F. = a + x.
Stevens, N. M. 1906.
Chelymorpha orgus. M. = 10 + y. F. = 10 + x.
Stevens, N. M. 1905,
Chlaemus aestivus. M. = a + y. F. = a + x.
Stevens, N. M. 1906.
Chlaenius pennsylvanicus. M. = a + y. F. = a + x,
Stevens, N. M, 1906.
Chrysochus auratus. M. = 12 + y. F. = 12 + x,
Stevens, N. M. 1909,
Cicindela primeriana. M. = 9 + y, F. = 9 + x,
Stevens, N. M. 1906,
Cicindela vulgaris. M. = 10 + y. F, = 10 + x.
Stevens, N. M, 1909.
Coptocyia aurichalcea. M. = 10 + y. F. = 10 + x.
iNfowlin, N. W. 1906.
Coptocycla clavata. M. = 8 + y. F. = 8 + x.
Stevens, N. M. 1909.
Coptocvcla guttata. H. = 8 + y, F. = 8 + x.
Nowlin, N. W. 1906,
Cylene robinia. M. = 9 + y...F, = 9 + x.
Stevens, N. M. 1909,
Doryphora clivicolis. M. = 16 + y. F. = 16 + x,
Stevens, N. M, 1909,
Doryphoria deoemlineata. M. = 17 + y. F. « 17 +
Stevens, N. M. 1906.
Epicauta cinerea. M. = 9 + y. F. = 9 + x.
Stevens, N. M. 1909,
Epicauta pennsylvanica. M. = 9 + y. F. = 9 + x,
Stevens, N, M. 1909.
Epilachna borealis. M, = 7 + y. F. = 7 + x.
Stevens, N. M. 1906.
Euchroma gigantica. M. 12 + y. F. = 12 + x.
Nichols, M. L, 1910,
Euphoria inda. M. = 9 + y, F. = 9 + x,
Stevens, N. M. 1906.
-9-
Coleoptera
Galerita bicolor. M. = a + y. F. = a + x.
Stevens, N. M. 1906.
Haltica chalybea. M. = 10 + y. F. = 10 + x.
Stevens, N. M. 1909.
Lema trilineata. M. = 15 + y. F. = 15 + x.
Stevens, N. M. 1909.
I.ina laponlca, M. = 16 + y. F. = 16 + x.
Stevens, N. M. 1909.
liistotrophus cingulatus. M. « 12 + y. F. = 13 + x
Stevens, N. M. 1909.
Obera tripunctata. M. = a + y. F. = a + x,
Stevens, N. M. 1909.
Odontota dorsalis. M. = 7 + y. F. = 7 + x.
Stevens, N. M. 1906.
Penthe obliquata. M. = 7 + y. F. = 7 + x.
Stevens, N. M. 1909.
Phytonomius punctata. M. = a + y. F. = a + x.
Stevens, N. M. 1909.
Silpha americana. M. = 19 + y. F. = 19 + x,
Stevens, N. M. 1906.
Staphylinus violaceus. M. = 21 + y. F. « 21 + x.
Stevens, N. M. 1909.
Tenebrio molitor. M. = 9 + y. F. = 9 + x.
Stevens, N. M. 1905.
Tetraopes tetraophthalmus. M. = 9 + y. F. = 9 + x
Stevens, N. M. 1909.
Trirhabda oanadense. M. « 14 + y. F. = 14 + x.
Stevens, N. M. 1906.
Trirhabda virgata. M. = 13 + y. F. = 13 + x.
Stevens, N. M. 1906.
Diptera
Anapheles pinctpennis. M, - 5 + y. F. = 5 + x.
Stevens, N. M. 1910.
Calliphora vomitoria. M. = 5 + y. F. - 5 + x.
Stevens, N. M. 1908a.
Culex pipiens. M. = 5 + y. F. = 5 + x.
Stevens, N. M. 1910.
Culex tarsilis. M. = 5 + y. F. = 5 + x.
Stevens, N. M. 1910.
Drosophila amoena. M. « 3 + y. F. - 3 + x.
Metz, C. W. 1914.
Drosophila ampelophila. M. = 3 + y. F. = 3 + x.
Stevens, N. M. 1908a.
Drosophila funebris. 1. - 4 + y. F. = 4 + x.
Metz, C. W. 1914.
Drosophila, quinaria. M. = 3 + y. F. = 3 + x.
Metz, C. W. 1914.
Drosophila repleta. M. = 5 + y. F. = 5 + x.
Metz, C. W. 1914.
Eristalis tenax. M. = 5 + y. F. = 5 + x,
Stevens, N. M. 1908a.
-10-
Diptera
Lucilia Caeaar. M. = a + y. F. = a + x.
Stevens, N. M. 1908.
Musoa domestica. M. = 5 + y. F. = 5 + x.
Stevens, N. M. 1908.
Phorbia brassica. M. = a + y. F. = a + x.
Stevens, N. M. 1908.
Sarcophaga sarraciniae. M. = 5 + y. F. = 5 + x
Stevens, N. M. 190Sa.
Scatophaga pallida. M. = 5 + y. F. = 5 + x.
Stevens, N. M. 1908a.
Tetanocera sparsa. M. = 5 + y. F. = 5 + x.
Stevens, N. M. 1908a.
Theobaldia incidens. M. = 5 + y. F. = 5 + x.
Stevens, N. M. 1910.
Hemiptera
Apiomerls crassipes. M. = 11 + y. F. = 11 + x.
Payne, F. 191S.
Banasa calva. M. = 13 + y. F. = 13 + x.
inison, E. B. 1907b.
Banasa diraidiata. M. = 7 + y. F. = 7 + x.
Wilson, E. B. 1907b.
Brochymena. M. « 6 + y. F. = 6 + x.
Wilson, E. B.
Calocoris rapidus. M. = 14 + y. F. = 14 + x.
Montgomery, T. H. 1906.
Coenus delius. M. = 6 + y. F. = 6 + x.
Wilson, E. B. 1905.
Cosmopepla carnifex. M. « 7 + y. F. = 7 + x.
Montgomery, T. H. 1906.
Diplocodus exsanguis. M. = 13 + y. F. = 13 + x
Payne, F^ 1909.
Enchenopa binotata. M. = 9 + y. F. = 9 x.
Kornhauser, S. I. 1914.
Eurygaster alternatus. M. = 6 + y. F. = 6 + x.
Montgomery, T. H. 1906.
Euschistus crassus. M. = 5 + y. F. = 5 + x.
Foot & Strobell. 1913.
Euschistus fissilis. M. = 6 + y. F. = 6 + x.
Wilson, E. E. 1905. (b & c) 1906.
Euschistus ictericus. M. = 6 + y. F. = 6 + x.
Wilson, E. E. 1906.
Euschistus servus. M. = 6 + y. F. = 6 + x.
Wilson, E. B. 1905.
Euschistus tristigmus. M. = 6 + y. F. = 6 + x.
Montgomery, T. H. 1901, 1906,
Euschistus variolarius. M. = 6 + y. F. = 6 + x
Wilson, E. B. 1906.
Lygaeus bicruris. M. = 6 + y. F. = 6 + x.
Wilson, E. B. 1913.
Lygaeus turcicus. M. = 6 + y. F. = 6 + x.
Wilson, E. B. 1905. (a & b) 1906.
-11-
Hemiptera
Metapodius (acanthocephala) feraoratue. /M. = 10 + y.
Wilson, E. E. 1909. IF. = 10 + x.
Metapodius (acanthocephala) granulosus. |M. = 10 + y.
Wilson, E. B. 1909. \f. = 10 + x.
Metapodius (acanthocephala) terminalis. fM, = 10 ■+ y.
Wilson, E. B. 1909. (F. = 10 + x.
Mormidea lugens. M. = 6 + y. F. = 6 + y,
Montgomery, T. H. 1906.
Nabis annulatus. M. = 8 + y. F. = 8 + x.
Montgomery, T. H. 1906.
Nezara Hilaris. M. = 6 + y. F. = 6 + x.
Montgomery, T. H. 1905. Wilson, E. B. 1910.
Nezara viridula. M. = 6 + y. F. = 6 + x.
Wilson, E. B. 1910.
Oebalus pugnax. M. = 4 + y. F. = 4 + x.
Wilson, E. B. 1910.
Oncopeltus fasciatus. M. = 7 + y. F. = 7 + x.
Wilson, E. B. 1913.
Peliopelta abbreviata. M. = 6 + y. F. = 6 + x.
Montgomery, T. H. 1906.
Peribalus lirabolaris. M. = 6 + y. F. = 6 + x.
Montgomery, T. H. 1906.
Perillus confluens. M. = 6 + y. F. = 6 + x.
Montgomery, T. H. 1906.
Podissus spinosus, M. = 7 + y. F. = 7 + x.
Montgomery, T. H. 1901, 1906.
Wilson, E. B. 1906,
Poecilocapsus goniphorus. M. = 16 + y. F. = 16 + x.
Montgomery, T. H. 1906.
Rocconota annulicornis. M. = IS + y. F. = 13 + 3x.
Payne, F. 1909.
Stiretrus anchorago. M. = 6 + y. F. = 6 + x.
Wilson, E. B. 1909.
Tingis clavata. M. = 6 + y. F. = 6 + x.
Montgomery, T. H. 1906.
Trichopepla seraivittata. M. = 6 + y. F. = 6 + x.
Montgomery, T. H. 1906.
Trichopepla. M. = 6 + y. F. = 6 + x.
Wilson, E. B. 1905.
Zaitha sp. M. = 11 + y. F. = 11 + x.
Montgomery, T. H. 1906.
Nematoda
Ascaris felis. M. = 8 + y. F. = 8 + x.
Edwards. 1911.
Orthoptera.
Anisolabis maritima. M. = 11 + y. F. = 11 + x.
Randolph, H. 1908.
Forficula auricularia. M. = 11 + y. F. = 11 + x.
Stevens, N. M. 1910.
de Sinety. 1901.
12-
TYPE III. n/2, n/2 + 2 or more x.
Arachnida
Agalena naevia. M. = 19. F. = 19 + 2x.
Wallace, L. B. 1908.
Pholcus phalange idee. M. = a. F. = a + 2x.
Wallace, L. B. 1908,
Maevia vittata. M. = a. F. = a + 2x.
Painter, T. S. 1913.
Hemipt era
Syromastes marginatus. M. = 10. F. = 10 + 2x.
Qross, J. 1904.
Nematoda
Ascarie lurabricoidee. M. = 19, F. = 19 + 5x.
Edwards. 1910.
Trenatoda
Schistosomum haematobium. M. = 6. F. = 6 + 2x.
Lindner, E. 1914.
Vertebrata
Pig. M. = 10. F. 10 + 2x.
Wodsedalek, J. E. 1913.
Homo sapiens. (man) M. = 10. F. = 10 + 2xf
Guyer, M. F. 1910.
Winiwarter, H. von. 1912. M. = 23. F. = 24
TYPE IV. n/2 + y, n/2 + 2 or more x.
Hemiptera
Acholla ampliata. M. = 10 + y. F. = 10 + 5x.
Payne, F. 1909.
Conorhinue sanguisugus. M. = 10 + y. F. = 10 + 2
Payne, F. 1909.
Fitchia spinosula. M. = 13 + y. F. = 12 + 2x.
Payne, F. 1909.
Gelastocoris (Galgulue) oculatus. M. = 15 + y. F
Payne, F. 1909.
Pnirontie modesta. M. = 10 + y. F. = 10 + 4x.
Payne, F. 1912.
Peelliodes cinctus. M. = 12 + y. F. = 12 + 3x.
Payne, F. 1912.
Prionidue cristatus. M. = 11 + y. F. = 11 + 3x.
Payne, F. 1909.
Thyanta calceata. M. = a + y. F. = a + 2x.
Wilson, E. B. 1909.
Sinea complexa. M. = 12 + y. F. = 12 + 3x.
Payne, F. 1912.
Sinea confusa. M. = 12 + y. F. = 12 + 3x.
Payne, F. 1912.
-13-
Heraiptera
Sinea diadema. M. = 12 + y. F. = 12 + 3x.
Payne, F. 1909, 1912.
Hemiptera
Sinea rileyi. M. = 12 + y. F. = 12 + 5x.
Payne, F. 1912.
Sinea spinipee. M. = 12 + y. F. = 12 + 3x.
Payne, F. 1912.
Nematoda
Ascaris lurrbricoidee. M. = 18 + x. F. = 18 + 5x.
Edwards, C. L. 1910.
TYPE V. n/2, n/2. (No observable difference in spermatozoa.
There may or may not be a difference In the eggs. )
Amphibia
Salamandra maculosa. M. = 12. F. = 12.
Schreiner, A. & Z. E. 1906b,
Coleoptera
Silpha carinata. M. =16. F. =16.
Holmgren, N. 1902.
Echinodermata
Aeterias vulgaris. M. =9. F. = 9.
Tennent, D. H. 1907.
Hemiptera
Brown Rose aphid. M. =5. F. = 5.
Green Rose aphid. M. =7. F. = 7.
Migratory Rose aphid. M. =9. F. = 9.
Saranac Willow aphid. M. =5. F. = 5,
Harpswell Willow aphid. M. = 3. F. = 3.
Aphis oenotherae. M. =5. F. = 5,
Oenothera aphid II. M. =4. F. = 4.
Black milkweed aphid. M. =4. F. = 4.
Orange milkweed aphid. M. =4. F. = 4.
Pale milkweed aphid. M. =7. F. = 7.
Nasturtium aphid. M. = ^. F. = 4.
Oak aphid. M. = 7. F. = 7.
Beach goldenrod aphid. M, =6. F. = 6.
Tall goldenrod aphid. M. =6. F. = 6.
Paper birch aphid. M. = 9. F. = 9.
Clover aphid. M. =8. F. = 8.
Woolly beech aphid. M. = 8..F. =8.
Star cucumber aphid. M. =5, F. = 5.
Maple aphid. M. = a. F. = a.
Pea aphid. M. =4. F. = 4.
Gourni aphid. M. =5. F, = 5.
Stevens, N. M. 1905.
-14-
leoptera
TermopeiB angusticollis. M. 26.
Stevena, N. M. 1905.
Lepldoptera
Abraxas. M. = 9. F, =■• 9.
Wilson, E. B. 1909.
Cacoecia cerasivorana. M. = a. F
Stevens, N. M. 1906.
Euvanessa antiopa. M. = a. F. =
Stevens, N. M. 1906,
Mollusca
Sagitta bipunctata. M. =9. F. =
Bordas, M. 1913.
Trichoptera
Platyphylax designatus. M, = 30.
Lutman, B. F. 1910.
UNCLASSIFIED FORMS HAVING SEX CHROMOSOMES:
Vertebrata
Daeypus sexcinctus (armadillo)
Patterson, N. F. 1910.
Bat.
Jordan, H. E. 1913.
Bos tauris (bull)
Jordan, H. E. 1913.
Scbnoenfeld, H, 1901.
Felie catus. (cat)
Saintmont, J, 1909.
Ca^nis farailiaris (dog)
Jordan, H. E. 191:^.
Equus caballus (horse)
Jordan, H. E. 1913.
Guinea pig.
Stevens, N. M. 1911.
Mule.
Jordan, H. E. 1913.
Rat.
Duesberg, J. 1909.
Ovis (sheep).
Jordan, H. E. 1913.
Mus sp. (white mouse)
Jordan, H. E. 1913.
-15-
4« Prevl ouB Work on Siz e Dlmorp hlBm
Dr. Charles Zeleny and Mr. K. C. Fauat published data
and curves for fifteen species of animals in the Journal of Ex-
perimental Zoology, Volume 18, Number 2, February, 1915. Alto-
gether they made thirty-three separate determinations. The sub-
jects used were Musca domeetica, Lygaeus kalmii, Alydus piloaulus,
Anasa tristis, Trirhabda toraentosa, Phytonomus punctatus, Mela-
noplue femur rubrum, Melanoplus dif f erentialis, Gryllus abbrevia-
tus, Aeshna canadensis, Rana pipiens, Pseudemys troosti, Ovis aries,
Eos taurus and Canis familiaris. Their general results indicate
that the population of spermatozoa from a single testes is made
up of two separate groups.
Mr. J. E. Wodsedalek published data on the pig in 1913
which indicates a bimodal curve in the spermatozoan population of
this animal.
II. MATERIAL AND METHODS
1. Most Desirable Speci es
The best species which could be used in a piece of work
of this character would be those in v*rhich the greatest chromosom-
al differences have been described. Such forms as Protenor bel-
fragei, Largu.s cinctus and others of like nature seemed highly
desirable. Forms for which figures of the chromosomes were pub-
lished were also desirable, as a calculated ratio obtained from
these figures would offer a standard for checking the actual ratio
obtained. The lengths of tte spermatozoa should vary as the cube
root of the total volume of the contained chromatin.
-16-
The most desira-ble species were not easily obtainable
inasmuch as in many cases sexual maturity occurs during the sum-
mer. Material from such species as could be found was mounted
and that which was seemingly the most desirable was used in the
measurements. A considerable number of insects hibernate be-
neath old boards, decaying bark, etc. The bases of mullein plants
often harbor many guests when other places are barren of life.
Insect testes are always located in the abdomen, usually
towards the tip and at the dorsal side. They are readily dis-
tinguished and are often yellow or red in color.
2. Fixat ion and Staini ng:
After experimenting with Delafield, Ehrlich and Heiden-
hain haeraatoxylins it was finally decided that Heidenhain's iron
haenatoxylin gave the best results. The testes were dissected
in normal salt solution. The spermatozoa, taken when possible
from the vas deferens, were smeared on an albumen coated slide
and fixed over osraic acid fumes. After a few seconds of treatment
with the osraic fumes they were allowed to just reach a dry condi-
tion, then washed in tap water and left in Heidenhain for several
hours. From the Heidenhain they were dipped in tap water and
left in a one half per cent solution of haematoxylin for 10-15
hours. The time factor seems to be unimportant if not too serious
ly abused. They were rinsed in tap water again and destained in
the Heidenhain. Destaining takes about eight minutes with a fresh
solution. When properly destained they were run up thru the al-
cohol series into xylol and mounted in balsam. In bringing the
-17-
elides over into the one-half per cent haematoxylin, a slight
amount of the Heidenhain is carried also. The iron in this aids
in giving a desirable intensely black stain.
3. Method of Measur ement
In all the sperm heads measured, the natural form seemed
to be a straight one. Many individuals were curved and twisted
on the slide. Of course, only the straight ones were measured.
It is necessary to accuracy that the spermatozoan be in a horizon-
tal position. No individuals were measured, all of whose length
was not visible at the same amount of focus in the microscope.
Measurements were made with a No. 2 Leitz ocular, A l/lZ oil
immersion objective was used. A mechanical stage obviated all
danger of duplicate measurements. In practically all cases sperma-
tozoa were measured to lengths of an ocular division. Personal
errors were eliminated as far as possible by numerous remeasure-
ments. Measurements were not made by poor light. No measurements
were made when fatigue might influence the result. Care was
taken to have all measurements made under as nearly the same con-
ditions as possible. Tabulation of data was not made until the
full number decided upon for the set had been completed. This
was to avoid danger of a false judgment and the selection of par-
ticular values.
4. Source s of Possible Error
Before accepting the results obtained all possibilities
of incorrectness must be considered. These fall into three
classes: 1. Mechanical erroB, those due to the personal equation
of the observer or other errors of measurement. 3. Errors due
-18-
to poor methods of technique. 3. Errors due to artificial demor-
phiam in the living material which might ensue because of the
presence of any one of a number of conditions.
k» Possible Mechanical Errors
a. All spermatozoa, all of whose length was not in
focus at the same time, were eliminated. It is possible that this
might occur more frequently with long individuals than with short
ones. This might produce asymmetry in a curve but there is no
reason to believe that it would result in bimodality.
b. Each set of measurements required a number of sit-
tings, usually twelve to fifteen. This number itself would tend
to prevent bimodality resulting from possible change of standards,
poor light, fatigue, etc,
0. The character of the scale might tend to cause
grouping around certain points. Thick lines might obscure the
nearest tenths, etc. The scale used had the narrowest lines of
any obtainable. Frequent remeasurements were made and final re-
sults did not show any grouping of this kind. Many spermatozoa com«
nearly between two units of measurement. Biased judgment resulting
from previous determinations, or an unbased hypothesis might
throw these into one group more frequently than another. In plot-
ting curves the obtained lengths were grouped by fifths while
measurements were made to tenths, thus counteracting this tendency.
B. Possible Errors of Technique
a. Lack of uniformity of fixation or staining on the
slide. Tabulations made by Zeleny and Faust for different regions
-19-
of the slide ehowed no deviation from the general diraorphlem.
b. Material at the edge dries more rapidly in the pro-
cess of fixation than that of the center. Tabulations by Zeleny
and Faust of material of the two regions showed no essential
difference between them.
o. Material drawn over a dlide by means of currents
set up in the suspending liquid may have smaller individuals at
one end of the smear than at the other. In the preparations made,
all material was equally distributed to all parts of the slide and
dried in position before staining.
d. In smearing material some spermatozoa may be
stretched or otherwise distorted. These are easily recognized
and were always eliminated.
e. Some spermatozoa may be curved. These were never
measured, only the straight individuals being used.
f. In case longer spermatozoa curved more often than
shorter ones a disparity of numbers might occur. However, this
would cause asymmetry rather than bimodality,
g. The chromatin rod usually takes an intense stain
and the cytoplasmic cap a light one. In cases of a short cap or
insufficient destaining there might be a tendency to measure to
the end of the head. This would produce apparent dimorphism.
C. Errors Due to Artificial Dimorphism in the Living Material
a. Error of random sampling. The spermatozoa taken
may not be representative of the mass for the entire testis. The
large number of individuals measured should prevent this possibilit]
-20-
"b. Two or more different degreeo of maturity may be
preeent in the material studied. Thia would give an apparent
dimorphiem. The use of material which was very active would tend
to eliminate this chance. The supposition would also involve
the hypothesis that there was an abrupt bree^k in continuity be-
tween two stages of development. This seems to be hardly likely,
o. Spermatozoa of like size may congreg-ate in masses
in particular parts of the vae deferens because of similarity in
physiological activity or perhaps mechanically. The entire con-
tents of the vas deferens were suspended in a drop of physiological
normal salt solution and the whole was thoroughly mixed before
making smears.
d. The chromatin rod length may not be a true index of
the length of the entire sperm head. As the chromatin rod repre-
sents nearly the entire length this objection is not to be con-
sidered seriously. Moreover quantitative difference in chromatin
content ciuet necessarily affect the head length of spermatozoa.
e. Spermatozoa from two different individuals might
show dimorphism not due to differences present within a single
testes. The fact that material used was taken from a single
testis removes this difficulty.
Other sources of error might be included. Tho se cited
are the ones regarded as most important. T^rea-rly all these possi-
bilities would cause asymmetry rather than bimodality. Moreover
the accumulation of data, practically all of which shows bimodality,
makes the supposition nearly incontrovertible that such bimodality
is due to the presence of two kinds of spermatozoa differing in
a
c
d
f
i
h
Spermatozoan heads
a. Leptocorls trivittatua
Id. Reduviolus ferus
0. Corizus lateralus
d. Euschistus variolariue
e. Cosmopepla carnifex
f. Passalus cornutus
g. Berosus striatus
h. HeliodriluB caliginosa
Magnification = 900
OF THE
UNIVERSITV OF ILLINOIS
-21-
chroniatin content.
DATA
T epto corle triyittatue
E. B, Wil6on (1906) states that this insect has two
kinds of spermatids, one containing seven and the other six chromo-
somes. This would put it in Type 1. No figures could "be obtained.
A rough comparison can be made by using the expected ratio of
Anasa tristis, another coreid, as its measure.
Material was obtained at Urbana in early March. One
testis, only, was used and this gave an abundance of straight
active spermatozoa. Nine hundred and eighty four measurements were
made. One unit on the ocular micrometer scale equals 1.717 microns
The resulting curve is noticeably bimodal, the modes coming at
25.4 microns and 27.8 microns. The length ratio is 25.4:27.8 =
1:1.09. The first five hundred measurements were used as a basis
for a curve and the remainder for another curve. The results
were bimodal curves with modes at 25.4 and 27.8. The expected
ratio of Anasa tristis is 1:1.11.
2. Reduviolus f eru s
No cytological data could be obtained for this form
but members of the same family have two kinds of spermatids accor-
ding to T. H. Montgomery (1909).
Material was collected at Urbana about the middle of
March. An abundance of active spermatozoa was taken from a single
testis. This gave plenty of straight heads after fixing and
staining. Five hundred measurements were made. One unit on the
LEPTOCORIS TRIVITTATUS
1. Value in microns 30.9 31.3 21,6 33.0 23.3 23.7 33.0 23.3
Frequency
icy
1
2
3
6
9
13
18
23.7
24.0
24.4
24.7
25.0
25.4
25.7
26.1
26.4
25
26
28
30
41
53
37
31
38
27.1
27.4
27.8
28.1
28.4
28.8
29.1
29, 5
29,8
41
50
60
51
45
41
39
38
40
30. 5
30.9
31.2
31.6
31.9
32.3
32.6
33
24
20
15
12
11
8
7
5
23
40
31
OF THE
UNIVERSITY OF ILLlNOlb
-22-
ocular micrometer scale equals 1.717 microns. The curve indicates
"bimodali ty, but would probably be improved by the addition of a
large number of measurements. The modes occur at 27.4 microns,
and 28.8 microns. The head length ratio is 27.4:28.8 = 1.00:1.05.
3. CorizuB late raluB
Montgomery (1906) states that this insect has two kinds
of spermatids, one having six and the other seven chromosomes.
This would place it in Type I. However, his figures are not large
enough to be of value in determining the approximate chromatin
ratio for the two spermatozoa. The expected ratio used was that
of Anasa tristis, another coreid.
Material was obtained at Urbana in late March and gave
an abundance of lively spermatozoa. These fixed in a satisfactory
manner. Two measurements, each of five hundred individuals, were
made. One division of the ooular micrometer equals 1.717 microns.
The second series is a check upon the first. In both cases bi-
modal curves resulted. The modes were alike coming at 27.1 microns
and 2S.5 microns. The head length ratio is 27.1:2S.5 = 1:1.09.
The expected ratio, that of Anasa tristis is 1:1.11. This is
probably a trifle high as Anasa tristis has an exceptionally large
"x" chromosome.
^* Euschi stus vari olarius
Wilson (1906) demonstrates that there are two kinds of
spermatids. The male producing ones have six normal chromosomes
plus a small "y" shromosome a-nd the female producers have six
normal chromosomes plus an "x" chromosome. This would place the
I I j
!
REDUVIOLUS FERUS 4
Value in microns
33.7
34.0
34.4
34.7
35,0
35,4
35.7
Frequency
4
5
6
5
13
19
35
36.1
36,4
36.7
37.1
37.4
37.8
38,1
38.4
38.8
30
35
36
49
56
45
33
37
35
39.1
39.5
39.8
30.1
30.5
30.9
31,3
31.6
31.9
33
18
18
10
9
8
7
5
4
33.3 33.6
3 1
1 1 1 1 1 1 1 1 1
-h
-
-H
4
H
-J
5#
4
+1
1
1
-- 4-
■H-
-
+
1
1
-4-
T
4- 11-
i
f-K
+4
!
-
-r
- J.
■
4
I
1
+
1 1
1
— 1
1
1 1
■
1
■H-
-*-r, — ^
-
"T
H
rr
-1
■
H
r
—
T
1
I
1
1
-l—A ^
L
1
rj-
!
4
1 1
— ^
-i-
+ '
h
-I —
r\
J-
4-
hi
+1
-H
I
t
r
-t-
-
[X
-
• I
•
T
-1-
-'-^
t
W
r
_.
ff
--++-
i
4-
t-
4-
r
4
t
1-
h
1
! —
-f-
:
■
U. OF I. 6. S. FORM S
3, Value in raicrona I.
Frequency
25.0
25.
4
25.7
13
14
16
28.4
28.8
29.1
13
19
26
31.9
32.
3
32.6
6
9
5
II.
25.4
25.
7
26.1
11
11
13
28.8
29.
1
29. 5
19
28
45
23.0
23.3
23.7
24.0
24.4
24.
7
7
8
10
13
13
13
26.1
26.4
36.7
27.1
27.4
27.
8
28.
19
23
27
42
30
15
11
29. 5
29.8
30.1
30.5
30.9
31.
3
31.
38
28
20
17
11
10
6
23.0
23,3
33.7
24.0
24.4
24.7
25!
4
6
7
7
5
7
11
26.4
26.7
37.1
27.4
27.8
28.
1
28.
20
27
54
32
20
21
17
29.8
30.1
30.5
30.9
31.2
31.
6
31.
30
15
12
10
7
8
4
32.3
5
32.5
5
U. OF I. S. S. rORM »
OF THE
UNIVERSITY OF ILLINOIS
-23-
Ineect in Type II. Wilson givee figures of the chromosomeB of
this species on page 15 of the Journal of Experimental Zoology for
1906. By computing their columee as cylinders the sum of the
volumes of the chomosomee of the two kinds of spermatozoa may be
obtained. The ratio of the cube root of these sums will be the
expected ratio of the spermatozoan heads. Length varies as the
cube root of volume.
Chromosome
Width
Length
Volume
a
2.8
3.1
19.085
b
2.5
3.7
18.16
c
2.6
4.0
21.24
d
2.8
4.3
26.48
e
2.2
3.0
11.41
f
1.9
2.1
5.95
X
1
1
0.79
X
2.4
2.4
10.86
Chromatin volume of male producing spermatozoan = 103.1104.
Chromatin volume of female producing spermatozoan = 113.1824.
Calculated ratio = 1.00:1.04.
Material was obtained in Urbana about the middle of
April. There was evidence that all of the spermatozoa were not
fully developed. This necessitated careful selection in making
measurements so as not to include unripe ones. These latter are
distingiaishable by their thickness and less definite outlines.
Five hundred measurements were made. One division of the ocular
micrometer equals 1.717 microns. The resulting curve is
Value in raicrone
13.0
13.4
13.7
14.1
14.4
14.7
15.1
Frequency
6
16
20
21
24
46
60
15.5 15.8
16.1
16.5
16.8
17.2
17.5
17.9
18.2
39 38
58
84
38
12
7
6
6
18.5
3
1
ttrr
U. OF I. S.
S. FORM 3
OF THE
UNIVERSITY OF ILLINOIS
-24-
conspicuously bimodal. The modes come at 15.1 microns and 16.5
microns. The head langth ratio is 15.1:16,5 = 1:1.09
5. Coamo pepla carn if ex
T. H. Montgomery (1906) states that this species has two
kinds of spermatids. The male producers have seven normal chromo-
somes plus a "y" chromosome and the female producers have seven
normal chromosomes plus an "x" chromosome. Thfe places the insect
in Type II. Such figures as are given were useless for computing
the probable head length ratio of the spermatozoa. This being
a Pentatomid, the same expected ratio was taken for ittliatwas used
for Euschistus variolarius. Material was obtained in Urbana in
early May. The mass of spermatozoa was uniformly active and took
a good fixation. Five hundred measurements were made. One divi-
sion of the ocular micrometer equals 1. 71 7microns. The resulting
curve shows well marked bimodality. The modes come at 18.5microns
and 19.9 microns. The head length ratio is 18.5:19.9 = 1:1.075.
The expected ratio is 1:1.05.
6. Passa lus cornutus
Ho published data could be obtained for this form.
Many varieties of beetles have been described by N. M. Stevens
and others. All. of these have "sex" chromosomes of one or
another of the described types; Nos. I and II predominating.
Material was obtained at Urbana in late March. The
spermatozoa were uniformly active and made a very good preparation.
Five hundred measurements were made. One division of the ocular
micrometer scale equals 1.717 microns. The resulting curve tends
towards unimodality. The slight projection at 12.4 may indicate
5. Value in microns
16.5
16.8
17.2
17.5
17.9
18.2
18.5
Frequency
6
14
16
19
26
42
83
18.9 19.2
19.6
19.9
20.3
20,6
20.9
21,3
21.6
53 35
42
68
37
14
11
11
9
22.0
8
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U. OF t. 6. S. FORM 3
UNlV£RSlTy^o"/lLUNa,.
-25-
either asymmetry or blmodality. A definite mode ocoure at 11.7
microns.
7, Berosus stria tue
No published data is available for use in judging this
form.
Material was obtained at Urbana in early April and gave
bounteously of active spermatozoa. Straight spermheads were in
profusion. Five hundred measurements were made. One division of
the ocular micrometer scale equals 1.717 microns. The resulting
curve is distinctly biraodal. The modes occur at 16.1 microns
and 17. S, The sperm head length ratio is then 15.1:17.2 = 1.00:
1.07.
8. Heliodr ilus caligin osa
This species is very interesting as it is hermaphroditic.
No doubt many zoologists would say without hesitation that a curve
of the head lengths of its spermatozoa would be unimodal. Un-
fortunately no published data giving a clear account of the sperma-
togenesis of the earth worm could be obtained.
Material was obtained at Urbana in April. Plenty of
functional spermatozoa were taken from the sperm ducts. The pre-
pared slides were not of the best quality as the sperm head out-
lines were not uniformly distinct and tended to distortion. Only
the best ones were measured. Five hundred measurements were made.
One division of the ocular micrometer equals 1.717 microns. The
plotted curve is flat topped. This would seem indicate bimodality,
but may be due to an insufficient number of measurements.
FASSALUS CQRNUTUS. -j.
6. Value in microns
10.15
10.3
10.
45
10.
6
' 10,8
11.
11.
15
Frequency
1
5
4
9
14
26
27
11.3 11.5
11.7
11.85
12.
12.
2
12.4
12.
55
12.
7
46 65
89
55
55
22
29
14
12
12.85 13 13.2
7 7 2
Mi, 1 i ■ '
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OF THE
UNIVERSITY or '
IBEROSUS STRIATUS
7.
Value in microns
13.7
14.1
14.4
14.7
15.1
15.
5
15.8
Frequency
4
9
9
10
14
33
41
16.1
16.5
16.8
17.3
17.5
17.9
18.2
18,
5
18.9
56
42
30
54
40
36
30
23
17
19.3
19.6
19.9
20.3
20.6
16
14
10
4
2
OF THE
UNIVERSITY OF ILLINOIS
Value in microns
13.0
13.4
Frequency
3
5
15.5
15.8
16.1
16.5
53
54
51
53
18.5
18.9
19.2
19.6
11
6
2
3
13.7
14.1
14.4
14.7
15.1
6
7
31
30
39
16.8
17.3
17.5
17.9
18.2
56
39
25
18
12
19.9
2
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U. OF I. S. S. FORM 3
I
UNIVERSITY OF ILlIimOIS
-26-
IV. DISCUSSION
While there has been written, in the past few years, a
vast number of articles dealing with spermatogenesis and tracing
"sex" chromoBomee as far as the spermatid stage of their existence,
there have been few attempts to demonstrate the effect of this une-
qual division, of the spermatogonial chromatin mass, upon the
spermatozoa. Nearly a hundred articles a year are being written
about spermatogenesis and yet only three papers have been published
in which actual tests have been made of spermatozoan dimorphism.
Yet the actual proof of the "x" chromosome hypothesis rests upon
recognition of differences in spermatozoan lengths, separation
of these lengths and artificial impregnation with the uniform
derived product.
Dr. Charles Zeleny amd Mr. E. Carrol Faust first recog-
nized the possibility of measuring dimorphism of spermatozoa and
introduced their problem by a preliminary paper on Anasa tristis
in 1913. This was followed by a large list of determinations in
1915. J. E. Wodsedalek (1913) measured dimorphism in the sperma-
tozoa of the pig.
There is practically uniform agreement that there is
dimorphism of spermatozoa, yielding female and male producing indi-
viduals. The ones with the larger chromatin content are commonly
acknowledged to be the female producers. Inasmuch as the members
of each group of this double spermatozoan population exhibit a
wide range of head lengths, the two groups must necessarily over-
lap and significant results in fertilization can only be obtained
-27-
by taking individuals of the extreme sizes.
The data in the papers of Zeleny, Faust and Wodsedalek
shows an expected bimodality in curves plotted from epermatozoan
head lengths, The data included in this paper agrees with that
of the above authors. The total accumulation of data includes
some twenty three different species and its very extent banishes
the possibility of obtained dimorphisms being due to any of the
recognized sources of error.
Six of the forms dealt with in this paper give undenia-
ble evidence of dimorphism of their spermatozoa. The seventh,
Passalus cornutus, seems to be unimodal and the eighth, Helio-
drilus caliginosa, gives a dif f icultly interpretable curve.
Passalus cornutus might be expected to exhibit bimodality
inasmuch as there are a great number of beetles having "sex"
chromosomes and practically none which may be definitely classed
as being without them. However, the plotted curve is unimodal
in character. This may arise in several ways. There may be
only one kind of spermatozoa. This seems to be improbable in
light of various cytological studies on beetle spermatogenesis.
There may be two kinds of spermatozoa formed, one of which
degenerates soon after formation. Morgan found this condition
to exist in the aphids and it has been reported in the spiders.
There may be two kinds of spermatozoa, the modes of which are so
close together that the combined curve appears unimodal. This is
the most probable explanation. In this form the modes might
conceivably be at 11,5 microns and 11.85 microns and be practically
-28-
equal in height. The number of individuals of 11.7 microns for
each group might be 3/4 of the number at the mode. The combined
number of individuals of 13.7 microns in length would be 1 l/S
times the number at each true mode and a false mode would be
created.
Heliodrilus callginosa is an hermaphrodite. Few ac-
counts of hermaphrodite spermatogenesis are to be found but such
authors as have published data upon the subject seem to uphold
the view that two kinds of spermatids are formed. Zarnik (1913)
traced the spermatogenesis of a parthenogenetic mollusc, Creeeis
arioula. He found that two kinds of spermatozoa were formed, one
of which was either nonfunctional or else degenerated. Schleip
(1913) believes that the spermatogenesis of parthenogenetic spe-
cies is the same as that of two sexed species. He thinks that
sex is confined to the sex organs and that the somatic cells are
neutral in regards to sex.
Boveri, Kreiger, and Gulick, have also investi-
gated the spermatogenesis of parthengenetic forms. Their concen-
sus of opinion seems to be that two kinds of spermatids are pro-
duced. It will be seen that there are several ways in which
spermatogenesis may develop in parthenogenetic individuals. Two
kinds of spermatozoa may be formed one of which is either not
functional or else degenerates. Two kinds of functional spermato-
zoa may be generated. One kind of spermatozoa may be formed. The
curve obtained is flat-topped. This indicates bimodality. The
modes probably come at 15.8 and 16.8 giving a ratio of 1:1.06.
-39-
ACKNOWLEDGMENTS
I can not thank Dr. Charles Zeleny too heartily, for it
ie his kind advice and endless patience which has made it possi-
ble for me to complete this thesis. I also am greatly indebted
to Mr. Hart of the State Entomological Laboratory for his care-
ful identification of the selected species of insects.
-30-
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-31-
V. SUMMARY
1. Cytological evidence accumulated by the leading
zoologists of the day shows that animals produce two kinds of
spermatids differing in chromatin content, this difference proba-
bly determining the sex of the fertilized egg.
2. This hypothesis must be tested by measurement of
dimorphism of the spermatozoa, separation of the two kinds and
artificial impregnation with the uniform product.
3. Since the spermatids receive different amounts of
chromatin, the spermatozoa must differ in size as they are almost
entirely composed of chromatin.
4. It is the object of this paper to demonstrate head
length differences in spermatozoa from single testes of the chosen
species.
5. Large range of variation was found in each case and
the size groups could only be made definite by a large number of
measurements and a plot of their size distribution.
6. Five hundred measurements was decided on as the mini-
mum number to be used.
7. The general result was a bimodal or two pointed
curve indicating the presence of two populations.
8. Wherever possible the ratio of these two modes was
compared with a ratio calculated from published figures of chromo-
somes of the species.
9. The general conclusion is that there are two size
groups in spermatozoa of a majority of animal species. This size
difference is correlated with a difference in chromatin content.
-32-
10. Acoording to cytological evidence the larger sperraa-
tozoa are female producing and the smaller are male producing,
11. The accumulated mass of data tends to eliminate
the possibility of the obtained results being due to any one of
the listed sources of error.
18. Leptocoris trivittatus. The observed ratio is
1:1.09.
13.
Reduviolus ferns. The observed ratio if 1:1.05.
14.
Corizus lateralus. The observed ratio is 1:1.09,
15.
Euschistus variolarius. The calculated ratio is
1:1.04.
The observed ratio is 1:1.09.
16.
Cosraopepla carnifex. The observed ratio is 1:1.075.
17.
Passalus cornutus. No observed bimodality.
18.
Berosus striatus. The observed ratio is 1.00:1.07.
19.
Heliodrilus caliginosa. The observed ratio is
1.00:1.06.
-33-
BIBLIOGRAPHY
Agar, W. E. 1911. The spermatogenesis of Lepidosiren paradoxa.
Quart. Jour. Mio. Sci. N. S. Vol. 57, part 1, pp. 1-44.
Arnold, G. A. 1908. The nucleolus and micro-chromosomes in the
spermatogenesis of Hydrophilus piceus. Archiv. fur Zell-
forschung. Vol, 2, p. 181.
Artom, C. 1909. Cromosomi ed eterocromosomi nelle cinesi spermato-
genetiche di "Stauronotus maroccanus". Biologica, Torino.
Vol. 3, No. 16, pp. 1-24.
Baehr, W. B, von. 1909. Die Oogenese bei einigen viviparen Aphi-
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Zellforsch., III. 1, 2.
1908. Uber die Bildung der Sexualzellen bei Aphididae.
Zool. Aijz. Bd, 33, pp. 507-517.
1907. Uber die Zahl der Richtungskorper in parthenogen-
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Zool. Jahrb. Anat. u. Ontog. 24.
Baltzer, F. 1909. Die Chromosomen von Strongylocentrotus lividus
und Echinus microtuberculatus. Arch, f, Zellforsch. II,
4,
1910. Uber die Beziehung zwischen dem Chromatin und der
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1909. Uber die Entwicklung der Echinidenbastarden mit
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Zool. Anz. Bd. 5.
Seeigl eiern. Verhandlungen der Deutschen Zoologischen
Gesellschaf t . Vierte Sitzung.
Baumgartner, W. J. 1904. Some new evidences of the individuality
of the chromosomes. Biol. Bull., Vol, 8, p, 1.
1902. Spermatid transformations in Gryllus assimilis witt
special reference to the nebenkern. Kansas Univ. Science
Bull., Vol. 1, p. 47.
Benda, C. 1905, Zur vergleichenden Spermiogenese der Amnioten.
Anat. Anz., Vol, 27, pp. 98-110.
Benedin, E. van, et Julin, C. 1884. La spermatogenese chez L'as-
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Berry, E. H. 1906. The accessory chromosome in Epeira. Biol. Bull.
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Blackman, M. W. 1905. On the Karyosphere and Nucleolus in the
spermatocytes of Scolopendra subspinipes. Pro. Am. Acad.
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1907, V. On the spermatogenesis of Lithobius. Proc. Amei ,
Acad. Arts ana Sci., Vol. 42, pp. 489-518.
1901. The spermatogenesis of the Myriapods. Bull. Univ.
Kansas 10.
1903. The spermatogenesis of Scolopendra heros. Bull.
Mus. Comp. Zool. Harvard., No. 48, pp. 1-138.
Bohmig, L. 1907. Zur Spermiogenese der Triclade Procerodes zer-
lachei n. sp. Arch, de biol. Vol. 23, pp. 1-12,
1908,
Chromosomen bei
-34-
Bonnevle, K. 1908. Chromosomenstuciien 1. (chromoeoraen von Ascar-
ie, Allium und amphiuma. ) Archiv. f. Zellf orschung. , Bd.
1.
1905. Das Verhalten der Chromatins in den Keimzellen
von Enteroxenos ostergreni. Anat. Anz. Bd. 26, pp. 374-
387.
1906. Untersuchungen uber Keimzellen 1. Beobachtungen
an den Keimzellen von Enteroxenos ostergreni. Jena.Zeit.,
Bd. 41, pp. 239-488.
Bordas, M. 1912. Contribution a 1* etude de la spermatogenese dans
le Sagitta bipunctata. La Cellule,, Vol. 28, pp. 165-214,
Boring, A. M, 1907. A study of the spermatogenesis of twenty-two
species of the Membracidae, Ja^oidae, Cercopidae, and Ful-
goridae with especial reference to the behavior of the
Odd Chromosome. The Jour, of Ex. Zool,, Vol. 4, p. 496.
1913. Chromosomes. The chromosomes of the Cercopidae.
Biol. Bull., Vol. 24, No. 3.
1913. Chromosomes. The odd chromosome in Cerastipsocus
venosus. Biol. Bull., Vol. 24, No. 3.
Bouin, P. and Bouin, M, 1903. La Spermogenese chez les Myriapodea.
Spermatogenese chez le Geophilus linearis. C. R. Soc.
Biol. Paris., Tom. 55, pp. 1060-1062.
1903. Sur 1' existence d'une double spermatogenese et de
deux sortes de spermatozoides chez Scolopendra raorsitans.
Arch. Zool. exper. eer. 4, Tom. 1, pp. 3-6.
Boveri, T. 1887. Zellen-Studien, Die Eildung der Richtungskorper
bei Ascaris megalocephala and Ascaris lumbricoides Jena.
1907. Zellenstudien VI. Die Entwicklung dispermer See-
igel-Eier, Ein Beitiag zum Befruchtungslehre und zu The-
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1909. Uber Beziehungen des chromatins zur geschlechts-
bestimraung. Sitzungsber. d, Phys. Med. Ges. Wiirzburg.
1908-09..
1912. ttber das Verhalten des geschlechtschromosomen bei
Herraaphroditismue. Beobachtungen an Rhabditis nigroveno-
sa. Verb. Phys. Med. Ges. Wursburg. , Bd. 41.
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