270 KELLOGG AND BELL 



distinct little 'black spots is surely a long and pronounced step 

 in pattern development. And every intervening numerical con- 

 dition is there ; two, three, four, five, six, seven, eight, nine, 

 ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen and 

 seventeen spots. But not only are all these discontinuous steps 

 there, but each is produced in from one to eleven ways, i. e., 

 by the various suppression of one or more of the modal twelve, 

 or the various addition of one or more spots to the modal pattern. 

 Natural selection has certainly every traditional opportunity 

 to make new kinds of lady-birds out of Htpfodamia conver- 

 gens. 



But can natural selection really takes advantage of these con- 

 ditions? This question brings us finally in the discussion of 

 this case of variation to what is in our minds, the point of by far 

 most interest and significance in the whole matter. It will be 

 recalled that all of the individuals studied were hibernating 

 insects assembled in large numbers. That is they are insects 

 which, hatched in the spring or summer (we do not yet know 

 whether the species is single, or several-brooded in this locality) 

 have undergone their exposed larval and pupal life, and an 

 active adult life from time of issuance from the pupal stage to 

 time of assembling for hibernation. It is a great pity that we 

 do not know exactly how long this time is ! The beetles have 

 been exposed however, to the struggle for existence ; have 

 competed for food and space ; have suffered heat and dry- 

 ness, and have tested their color pattern for whatever use 

 it exists for. The lady-birds although small are almost 

 all brightly and conspicuously marked and are believed by 

 most naturalists to be inedible (ill-tasting to birds) and to be pro- 

 tected by their bright conspicuous warning color pattern. If so, 

 the color of our hibernating thousands of Hrppodamia has been 

 put to some test of its usefulness. And all of the hibernating 

 thousands have survived whatever fate may have come to other, 

 to us unknown, thousands. But our variation series are from 

 the saved thousands. Hifipodamia with no spots, with one 

 spot, with two, three, eight, eleven, fourteen, sixteen, seven- 

 teen, eighteen spots have survived the struggle (for a brief 

 or longer period), and have gathered from far and near to 



