Sometimes I see a specimen of Leiobunum blackwalli in my garden. The females of this species have a dark saddle that widens towards the back part of the abdomen and then terminates abruptly: The males do not have such a pronounced saddle, but are easily distinguished from L. rotundum -which they resemble very much- by the pale ring around each eye where L. rotundum has an entirely dark/black eye hill. (Click to enlarge pictures)
L. blackwalli is often found in deciduous forest with dense undergrowth, along forest edges and waterways, in open fields and along the coast. In cities and villages L. blackwalli is much less common than L. rotundum, but not rare either. It is thought that L. blackwalli has decreased in numbers after the invasion of Opilio canestrinii (see last post), but unfortunately its distribution is not monitored well enough to know for sure.