(Xysticus gulosus, Keys.)
Like the beasts of prey which lurk around the water holes of African deserts, waiting for the feebler game to come down to drink, the crab spiders conceal themselves around the nectar-bearing discs of flowers. These nectar cups are the feeding places of thousands of sucking creatures, and the tragedies which take place in the shadows of the rose or lily petals are things we do not like to think of, for they are quite as real, quite as horrible and bloody struggles as those upon a larger scale, the very thought of which makes our blood run cold.
The crab spiders cannot run forward but dart sidewise and backward at great speed. One cannot help wondering if this ability may not often be an advantage rather than a drawback and enable the creature to surprise its prey by turning its back on it, something as a left-handed man often surprises an antagonist.
That these spiders run their own grave risks in this life around the nectar “water holes” is evident, for they form a large proportion of the food of mud wasps and if you want a handful of them, tear down a few mud daubers’ nests sometime in June and empty out their contents. The brilliant colors will surprise you and suggest that possibly the yellow ones haunt the yellow flowers and the blue the blue ones.
The particular species whose low, sprawling form is shown in the photograph is one of forty occurring in the United States and, although it is only from a fourth to a third of an inch long, is considered one of the large species. It is dull-colored, and, unlike its gaily-colored relatives, awaits its prey under bark and stones.
It spins no web and the small male leads a thoroughly vagabond life, whereas the female, in most species at least, settles down toward the end of her life and, after depositing her silken lens-shaped sac of eggs in some protected spot, she lingers near as if to guard it till she dies.
A FRONT VIEW OF A MATURE MALE SPIDER