There is a pervasive contrast in the early natural history writings of the co-discoverers of natural selection, Alfred Russel Wallace and Charles Darwin. In his writings from South America and the Malay Archipelago (1848-1852, 1854-1862). Wallace consistently emphasized species and genera, and separated these descriptions from his rarer and briefer discussions of individual organisms. In contrast, Darwin's writings during the Beagle voyage (1831-1836) emphasized individual organisms, and mingled descriptions of individuals and groups. The contrast is explained by the different practices of the two naturalists in the field. Wallace and Darwin went to the field with different educational experiences and social connections, constrained by different responsibilities and theoretical interests. These in turn resulted in different natural history practices; i.e., different habits and working routines in the field. Wallace's intense collecting activities aimed at a complete inventory of different species and their distributions at many localities. Darwin's less intense collecting practice focused on detailed observations of individual organisms. These different practices resulted in different material, textual and conceptual products. Placing natural history practices at the center of analysis reveals connections among these diverse products, and throws light on Wallace and Darwin's respective treatment of individuals and groups in natural history. In particular, this approach clarifies the relation between individuals and groups in Wallace's theory of natural selection, and provides an integrative starting point for further investigations of the broader social factors that shaped Victorian natural history practices and their scientific products.