MAYER: COLOR AND COLOR-PATTERNS. 223 



many other cases the outei" black and middle black are completely 

 fused, so far as the upper surface of the wings is concerned ; but, 

 if one examines the under surface of the hind wings, it will be 

 found that a narrow rufous streak still persists between the middle 

 black band and the outer black margin of the hind wing. 



(8) Variatioyis of the Marginal Spots of the Fore Wing. The 

 margmal spots are found very near the outer margin of the fore 

 wing; they are usually either yellow or white, but in some few 

 cases they are rufous. It appears from Table 9 that they are 

 present in 146 and absent in 254 species of the 400 Danaoid Heli- 

 conidae kno^m to me. Fig. 101, Plate 10, shows graphically 

 the manner in which these spots occur in those species which 

 possess them. It is evident from this curve that the number of 

 these spots is not determined merely by chance, for they show a 

 marked tendency to appear either as "2 or 3, or as 6 or 7 spots. 

 It is due to this fact, that there are two maximum points upon 

 the diagram Fig. 101, Plate 10. In those species which exhibit the 

 " 2- or 3-spot " condition, the spots are found near the front aj^ex 

 of the fore wing. In tlie " 6- or 7-spot " condition they lie aU along 

 the outer margin of the fore wing, one spot in each cell. In the 

 genera Ithomia, Xapeogenes, and especially in Ceratinia these mar- 

 ginal spots have become large and conspicuous ornaments. (See 

 Fig. 49, Plate 4.) 



Table 22 shows the manner of appearance of these spots in the 

 genera Heliconius and Eueides. They are found in only 26 species 

 of the 129 known to me ; and this number is far too smaU to war- 

 rant general conclusions concerning the order of their appearance. 



(9) The Marginal Spots of the Hind Wing. Table 14 illus- 

 trates the manner in which the marginal spots of the hind wings 

 make their appearance. They are absent in 279 and present in 

 121 of the 400 species of the Danaoid group. Thus they occur 

 rather less frequently than the marginal spots of the fore wing. In 

 the 121 species in which these spots are found they show a decided 

 tendency to appear either as 4 or as 5 spots. Fig. 102, Plate 10, 

 is a graphic representation of the distribution of these spots, derived 

 from Table 14. It appears that the outline of the figure approaches 

 a ])robability curve, and is approximately symmetrical about the 

 mean ordinate (A, B), situated at 4.54. 



