Alexander Skutch, author of A Naturalist in Costa Rica, in contrasting the perspectives of the scientist and the naturalist said the latter finds . . . the concrete significance of living things in their natural setting is at least as precious as any generalization. And one of the challenges of finding jumping spiders where they live is their size. Although not commonly referenced in the arachnid literature the Itsy Bitsy Spider nursery rhyme gives a useful characterization of size for many jumpers. Take a look at the habitat image below and see if you can find the spider. A sharp-eyed naturalist (not me) saw this Naphrys acerba as we walked along a trail at the Sabal Palm Sanctuary in the Lower Rio Grande Valley. The fact that most of our group walked right past the jumper demonstrates the soundness of the tactic of sitting in one place and looking, not for a particular spider, but for movement. Many jumping spiders, including those in the genus Naphrys (formerly Habrocestrum), are definitely itsy bitsy (3-5 mm).
Skutch, 1971; Edwards, (2002) 2003a