Zacheus crista is a large long-legged harvestman of Phalangiidae family, it is a rare species. Although spiders and opiliones are arthropods and belong to the same animal class (Arachnida), opiliones are not spiders. Opiliones, sometimes mistaken for spiders, are known by some as “harvestsmen,” while others call them “daddy longlegs.” Spiders in the family Pholcidae also are called “daddy longlegs”, but they are known more commonly as cellar spiders. People confuse these two long-legged arachnids, and while they may look similar, numerous differences have been discovered and observed in all aspects of their lives. Spiders have two visible body segments – the cephalothorax, which is the rounded head section, and the cylindrical abdomen. The opiliones’ body appears to have a single oval-shaped body segment. Average cellar spider’s body length is less than half an inch and its legs are up to 1.25 inches. Opiliones, or harvestmen, have a body length of about half an inch and legs as long as 6 inches. Opiliones' legs act as shock absorbers, which allow the body to move easily, they are detached easily and twitch after removal, perhaps to distract predators. Spider’s legs are not as long, nor do they spend as much time on the ground as do opiliones, they are more comfortable in their webs and, when not in their webs, these spiders walk unsteadily, with a bouncing action. Harvestmen have one pair of eyes, on a bump on the top of their head above their torso. Their eyesight is poor, the eyes are only able to detect moving objects a few feet away, so they use their longest legs (the second pair), as feelers as they wander. Spiders have six to eight eyes, and six of the cellar spider’s eyes are in two groups of three, with the two smaller eyes together in the center. Spiders eat insects, spiders and other small invertebrates. Opiliones are predators and scavengers. They typically are carnivorous and eat live invertebrate prey, such as beetles, earthworms, caterpillars, aphids, mites, small slugs, snails, flies, and spiders. They chew and swallow small bits of solid food, unlike spiders, which suck up their liquefied food.

Zacheus crista - это большой сенокосец семейства Phalangiidae, редкий вид. Хотя пауки и сенокосцы являются членистоногими и принадлежат к одному и тому же классу животных паукообразные (Arachnida), сенокосцы (отряд Opiliones) - не пауки. Существуют схожие пауки семейства Pholcidae, которые также имеют длинные ноги (чаще всего живут в подвалах), это «пауки-сенокосцы”. Люди путают эти виды длинноногих паукообразных и называют и тех, и других “daddy longlegs” («папа-длинные ножки»). В то время, как они могут выглядеть одинаково, в их жизни обнаружены и наблюдаются многочисленные различия. Пауки-сенокосцы имеют два видимых сегмента тела, сенокосцы - один видимый сегмент тела. Пауки-сенокосцы, как правило, имеют меньшие размеры, длина тела составляет 2—10 мм, ног до 50 мм. У сенокосцев тело обычно небольшое, 1—5 мм, ноги иногда чрезвычайно длинные - до 160 см.