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BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY. 





EXPLANATION OF PLATES. 



All the drawings were outlined with a camera lucida; tube length, 160 mm. pro- 

 jection on the table. Zeiss lenses were used, except where especially specified. 

 Distaplia occidentalis is figured in all cases where the name of the species is not 

 mentioned. All the figures were drawn from sections, except where the contrary 

 is stated. The combination of lenses oftenest used was a y ? immersion objective 

 and No. 2 ocular, and these, together with the camera, gave a magnification of 

 1300 diameters. Where no lenses and magnifications are mentioned this is the 

 combination used. 



LIST OF ABBREVIATIONS. 



