2Q2 ELIZABETH A. SMITH. 



EXPLANATION OF PLATES. 



Unless otherwise indicated the figures are drawn at a magnification of 2,700 

 diameters. The drawings of the fresh material are made with a magnification of 

 1,500 diameters. Fig. 24 is magnified 3,900 diameters. Plate I. is reduced one- 

 third while Plates II. to VI. inclusive are reduced one-fifth. The nuclei drawn 

 are usually from sections not directly through the center of the cells, as they con- 

 tain less chromatin and are consequently clearer. 



PLATE I. 

 Sympetrum semicinctum (Say). 



FIG. I. A drawing of the nymph of Sympetrum semicinctum (Say). 

 FIG. 2. A cross-section of the testis of a nymph. 



