▁in ▁colour . ▁The ▁ab dom inal ▁set ae ▁are ▁also ▁similarly ▁col oured . ▁They ▁have ▁eight ▁eyes ▁arranged ▁in ▁two ▁rows . ▁ ▁E col ogy ▁and ▁behavior ▁ ▁P lect re ur ys ▁tr ist is ▁are ▁the ▁inhabitants ▁of ▁ar id ▁and ▁semi - ar id ▁regions ▁of ▁south - western ▁North ▁America ▁including ▁California , ▁Nev ada , ▁Id aho , ▁Arizona ▁and ▁Ut ah . ▁Some ▁are ▁also ▁reported ▁from ▁Central ▁America ▁and ▁Mexico . ▁They ▁are ▁found ▁in ▁desert s , ▁dry ▁wood lands , ▁and ▁con ifer ous ▁for ests ▁up ▁to ▁ 2 , 0 0 0 ▁m . ▁They ▁make ▁web s ▁under ▁rocks , ▁woods ▁and ▁other ▁materials ▁available ▁on ▁the ▁dry ▁lands ▁of ▁their ▁natural ▁habit ats . ▁They ▁also ▁spread ▁to ▁urban ▁areas ▁building ▁web s ▁at ▁all ▁convenient ▁places . ▁Gener ally , ▁only ▁females ▁and ▁imm ature ▁ones ▁remain ▁in ▁the ▁web , ▁and ▁adult ▁males ▁w ander ▁around ▁especially ▁at ▁night . ▁The ▁sp iders ▁are ▁quite ▁vis ually ▁weak ▁even ▁during ▁hunting , ▁but ▁the ▁ven om ▁is ▁powerful ▁for ▁killing ▁or ▁par al ys ing ▁other ▁ara chn ids . ▁ ▁Ven om ▁ ▁The ▁ven om ▁of ▁P lect re ur ys ▁tr ist is ▁contains ▁a ▁number ▁of ▁complex ▁comp ounds . ▁The ▁ven om ▁is ▁a ▁calci um ▁channel ▁block er , ▁specifically ▁in hib iting ▁N - type ▁Ca 2 + ▁channels , ▁and ▁other ▁un ident ified ▁calci um ▁channels