590 CLAEENCE E. McCLUNG 



Della Valle. Paola 1912 La morphologia della chromatina dal punto di 



vista fisico. Archivio Zoologico Italiano, vol. 6. 



1913 Die Morphologie des Zellkerns und die Physik der Kolloide. 



Zeitschrift fiir Chemie und Industrie des Kolloide, Bd. 12. 

 Hance, R. T. 1917 The somatic mitoses in the mosquito, Culex pipiens. Jour. 



Morph., vol. 29. 

 Holt, Caroline 1917 Multiple complexes in the alimentary tract of the 



mosquito. Jour. Morph., vol. 29. 

 Whiting, P. W. 1917 The chromosomes of the common house mosquito, Culex 



pipiens, Linn. Jour. Morph., vol. 28. 



DESCRIPTION OF PLATES 



All figures are drawn at an initial magnification of 2860 diameters under the 

 camera lucida, and appear in the reproduction at a magnification of 1800. The 

 photomicrographs were obtained with a Zeiss 2 mm. objective of 1.40 N. A., 

 projection ocular 4 and a Watson 'Holoscopic' oil immersion condenser. The 

 original magnification of 1000 diameters is here reduced to 666, except fig. IX. 



PLATE 1 



EXPLANATION OF FIGURES 



Horizontal rows represent complete first spermatocyte complexes, usually in 

 lateral view, numbered 1 to 6. These are arranged so that chromosomes of 

 homologous size are brought into vertical rows, numbered from 1 to 12. Blank 

 spaces in vertical rows represent the normal position of the accessory chromosome 

 which is joined to a tetrad. 



1 A complex of Hesperotettix brevipennis. All twelve chromosomes are 

 free. 



2 Hesperotettix festivus, polar view. 



3 Hesperotettix viridis, class 1 — twelve chromosomes plus a supernumerary. 



4 H. viridis, class 2. 



5 Hesperotettix pratensis. 



6 Hesperotettix speciosus. 



