56 RECORDS 



band extended ; the results show that each row of spots or 

 bands exhibits a decided tendency to be of uniform color 

 throughout, that rows very rarely break at or near the middle 

 of their extent, and that the end spots of a row are more variable 

 than those spots near the center. " Frequency polygons " were 

 obtained from the above-mentioned data, for the rows of mark- 

 ings, for the number of spots in each row, and for the extent of 

 bands measured in interspaces. Eight such frequency polygons 

 were determined for the spots and bands on the upper and 

 lower surfaces of the wings in the group of Papilio Ornithoptera. 

 Of the four representing the conditions in the fore-wing, three 

 exhibit two well-marked maxima, the numbers being arranged 

 in descending series on either side of each. These maxima are 

 three and nine spots, or bands extending over three or nine 

 interspaces. If, now, Papilio be divided into the three sub- 

 genera Papilio s. str., Cosmodesnnis, and PJiarmacophagus, and 

 be still further separated into the African, Indo-Australian, 

 Europ-Siberian, and American forms, it is found that the insects 

 of the subgroups still display the tendency to have three or 

 nine spots, or bands extending over three or nine interspaces. 

 This is not a matter of correlation, for only 32 of the 453 species 

 of Papilio display both three and nine spots upon their fore- 

 wings. It is somewhat difficult to explain this condition upon 

 the hypothesis of natural selection, owing to the fact that 

 Papilios of widely separated regions show the same tendency to 

 produce these two maxima in the same manner. The Hes- 

 peridae and Castina show no such tendency, hence it is not uni- 

 versal for Lepidoptera. If it be due to natural selection acting 

 upon Papilios and restricting them to this condition, such selec- 

 tion must be universally operative in the case oi Papilio, but not 

 in the other species. It is easier, therefore, to assume a race 

 tendency in Papilio to produce either three or nine spots upon 

 the fore-wing, or bands extending over three or nine interspaces. 

 Other results, quantitatively expressed, were brought out by the 

 author. 



Mr. Trowbridge gave the result of observations on flying 

 birds for the purpose of showing that the emarginate primaries 



