STUDIES OF VARIATION IN INSECTS 269 



75. //. convergens; aberr. C,. "Nine-spotted lady-bird," 

 spots 2'", 3"' and 4'' being absent. 



76. H. convergens; aberr. C3. ''Nine-spotted lady-bird," 

 spots i', 5', 5'", 6' and 6"' being absent and an additional spot 

 between 3'' and 4' and another in front of 3' being present. 



77. H. convergens; aberr. D^. ''Eight-spotted lady-bird," 

 spots 5\ I'', 4'', 5% and 6'" being absent and an additional spot 

 between 2^ and 3^ being present. 



78. H. convergens; aberr. G^. "Five-spotted lady-bird," 

 spots 2\ 3^, 2'', 3'' and an additional spot near 3^ being present. 



79. H. convergens; aberr. H^. "Four-spotted lady-bird," 

 spots 3^ 3'", 5' and 5' being present. 



80. H. convergens; aberr. \. " Two-spotted lady-bird," 

 spots i^ and i'' being present. 



81. H. convergens; aberr. T3. "Two-spotted lady-bird," 

 spots 2^ and 2" being present. 



82. H. convergens ; aberr. L^. " Fourteen-spotted lady-bird," 

 spots i^ and i' being absent, one additional spot between i^ and 

 2^ two extra spots between 4^^ and 5% and one between 3' and 5"". 



83. H, convergens; aberr. Mg. " Fifteen-spotted lady-bird," 

 spots i^ being absent, one extra spot in front of 3'', two extra 

 spots between 3^ and 5^ and two more between 3'" and 5''. 



This list of " aberrations " is of interest not merely as an illus- 

 tration of the difficulties that the systematic entomologist (zoolo- 

 gist) has to face when he undertakes to "refine" his specific 

 descriptions, but as an illustration of the unexpectedly large 

 degree of variation which may be discovered^ by the careful 

 examination of a considerable series of individuals of a single 

 species. The great dominance of the 12-spotted mode, 90 per 

 cent, of all individuals examined (over 3,000), leads one to find, 

 nine times out of ten, individuals of this species with 12 spots. 

 The species is rightly described as 12-spotted, and the system- 

 atist may rest there. But what a revelation to the student of 

 variation ! What possibilities for the beginnings of new species 

 if variation in the color pattern is worth while, and capable of 

 being naturally selected ! 



From a red-brown lady-bird without a black spot to give it 

 pattern or conspicuousness to a lady-bird all dotted over by 18 



Proc. Wash. Acad. Sci., Dec, 1904. 



