Which ant is characterized by being 1/18" long with a velvety sheen and one node?

The choice of the odorous house ant is correct because this species typically measures around 1/18 inch in length, which aligns with the size described in the question. Additionally, the odorous house ant is known for its distinctive velvety sheen and the presence of a single node, which differentiates it from other ant species.

The velvety appearance of the odorous house ant is due to its fine, dense hair that covers its body. The single node between the thorax and abdomen is a crucial identifying feature that helps in distinguishing it from other ants that may have two nodes or none at all.

Understanding the physical characteristics of the odorous house ant and its unique features aids pest control professionals in accurately identifying it during inspections, thus facilitating effective management strategies.