EXPLANATION OF FIGURES. 



Each drawing was outlined with an Abbe camera lucida. The numbers of 

 the dorsal nerves are indicated by Roman numerals. Unless otherwise stated, 

 dorsal is up in all figures. 



Abbreviations. 



N. B. — Unfortunately an entirely consistent system of lettering figures 

 could not be adopted owing to the incorporation of the provisional lettering 

 in the drawings themselves. With the reduction in size accompanying the 

 reproduction of the figures, many of these letters are extremely small. For 

 explanation of all letters not embraced in the following list, the reader may 

 consult the explanation of the Figure on which the letters occur. 



