. Carnegie Institution of Washington publication. COLORATION IN POLISTES. 6i From these determinations it is apparent that a positive correlation exists between the degree of melanism of the abdomen and that of the thorax and the ch'peus. The curves shown in figs. 22, 23, and 26 represent these relations between the clypeus and abdomen graphically. This same tendency toward melanism in the northern forms is observed in the rubiginosiis group. Here the lighter species, such as texanus and bellicostcs, predominate in the narrow coastal region, while the group, so far as it is found to the northw

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. Carnegie Institution of Washington publication. COLORATION IN POLISTES. 6i From these determinations it is apparent that a positive correlation exists between the degree of melanism of the abdomen and that of the thorax and the ch'peus. The curves shown in figs. 22, 23, and 26 represent these relations between the clypeus and abdomen graphically. This same tendency toward melanism in the northern forms is observed in the rubiginosiis group. Here the lighter species, such as texanus and bellicostcs, predominate in the narrow coastal region, while the group, so far as it is found to the northw
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Image ID: RFRWJB
. Carnegie Institution of Washington publication. COLORATION IN POLISTES. 6i From these determinations it is apparent that a positive correlation exists between the degree of melanism of the abdomen and that of the thorax and the ch'peus. The curves shown in figs. 22, 23, and 26 represent these relations between the clypeus and abdomen graphically. This same tendency toward melanism in the northern forms is observed in the rubiginosiis group. Here the lighter species, such as texanus and bellicostcs, predominate in the narrow coastal region, while the group, so far as it is found to the northward, is represented by the dark uniformly colored rubiginosus. Just as striking, perhaps, as the relation between melanism and lati- tude, is the prevalence in the arid regions of Arizona and New Mexico of the yellow species, P. flaviis and P. aiirifer, and even P. navajoe.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Carnegie Institution of Washington. Washington, Carnegie Institution of Washington