This pattern appears to be an example of Allen 's rule .
This pattern is seen in other New Zealand Pompilids but is less marked in E. insularis due to its greater extent of sexual dimorphism with the males always being more uniformly dark .
This pattern appears to be an example of Allen 's rule and is seen in other New Zealand Pompilids but is less marked in E. insularis due to its greater extent of sexual dimorphism with the males always being more uniformly dark .