The ability of Habrocestum pulex, a myrmecophagic jumping spider, to detect olfactory and contact chemical cues from ants was investigated experimentally. When given a choice between walking over clean soil or soil that had housed ants, H. pulex spent significantly more time on ant-treated soil. However, H. pulex did not appear to discriminate between clean blotting paper and blotting paper over which ants had walked. In tests using a Y-shaped olfactometer, when given a choice between an experimental arm containing air from a cage containing ants, or 6-methyl-5-hepten-2-one, and a control arm containing clean air, H. pulex moved into the experimental arm significantly more frequently than the control arm. When on soil that had previously housed ants, agitated walking, undirected leaping, posturing with body raised, and perching on top of corks were each significantly more prevalent than when H. pulex was on clean soil. Chemical cues left by ants on soil also affected H. pulex's attention to visual cues from ants: when on treated soil, H. pulex initiated and completed stalking sequences more often, and after shorter latency, than when on control soil.