190 THE AMERICAN NATURALIST [Vol. LVI 



The commonest type of color pattern, in Chatopieura apiculata, 

 is one which involves a double band of blackish or grayish pig- 

 ment running the length of valves 2 to 8, the bands joined on 

 2 and on 8 by continuous semicircular blotches (cf. Fig. 1, cZ). 



In 3 out of 219 specimens, however, a central dark stripe, 

 clearly marked on valves 2 to 8 inclusive, accompanied a much 

 fainter double band extending to valve 1 (Fig. 1, 6), and made 

 up of regular triangular grayish blotches on the posterior bor- 

 ders of valves 2 to 7. In one case, a bright central band of white 



was marked by a median grayish blotch on valves 3 to 7 (Fig. 

 1. ; a paler example of the same kind is shown in Fig. 1, e. 



Tliese are instances where variation from the more usual color 

 type clearly has taken place simultaueously in the whole series 

 of valve-i)lates, this condition being seen not only in the form of 

 the central stripe, but also in the shapes of the individual pig- 

 ment blotches comprised in tlie double band (ef. Fiir. 1. a and b), 

 as well as in a few cases where three small but distinct i)igment 

 flecks were noted on the lateral field of eadi plat.'. 



In^ addition, however, two sorts of i)attern vjirlation^ occur 



definite yellow or orange central blotch ;it»i'<';ir.Ml on valve 2, and 

 nowhere else (Fig. 1, c) . And in five fiii'ihri- instances there was 

 found a marked blackish blotch at either lateral margin of valve 



