In a maritime slope bog of Maine, females of Eris militaris (Hentz, 1845) and Synageles canadensisCutler, 1988 nest in distinctly different floral parts of Northern pitcher plant (Sarracenia purpurea L.) (Sarraceniaecae) seed heads. Females of E. militaris spin egg retreats on the umbrella; females of S. canadensis spin egg retreats chiefly within locules of the ovary. In these intrafloral microhabitats, juvenile salticids are more prevalent than adults; females more prevalent than males; overall, multiple occupants are more prevalent than single occupants. Other than body size, the behavioral-structural attributes leading to this microhabitat preference for egg laying are unknown.