[Illustration: FIG. 433. Tubular nest of Zilla atrica.] [Illustration: FIGS. 434, 435, 435_a_. Male palpi of Zilla.--434, Zilla atrica. 435, Zilla x-notata. 435_a_, Zilla montana.] $Singa pratensis.$--The Singas are small Epeiridæ a sixth or fifth of an inch long, with smooth bodies and bright colors. They live among grass and other small plants in low open ground. When full grown the females of _S. pratensis_ are a fifth of an inch long, with the abdomen oval and marked with a double white stripe in the middle and a single one on each side. The cephalothorax is yellow, with a little black between the middle eyes not extending to the lateral pairs. The legs are yellow, without rings or other markings. The abdomen is yellow brown, darker toward the hinder end, with white or light yellow stripes. The under side is the same yellow-brown color, darker in the middle, with two narrow, curved, light lines from the spiracles to the spinnerets. The males are marked in the same way and have a smaller abdomen and longer spines on the legs. [Illustration: FIG. 436. Markings of the back of Singa variabilis.] $Singa variabilis.$--This is a little smaller than _pratensis_, usually about a sixth of an inch long. The legs and cephalothorax are bright orange color. The front of the head between the eyes is black. The abdomen is usually entirely black, but occasionally has bright yellow markings (fig. 436) arranged somewhat as in _pratensis_. Sometimes there is a wide middle stripe, with narrower ones at the sides and two underneath. Sometimes there are only the two lateral stripes, and there are all variations between these markings. The males are colored in the same way and have the same varieties. They are smaller than the males of _pratensis_, but have the palpal organs as large or larger. THE GENUS ACROSOMA [Illustration: FIG. 437. Web of Acrosoma spinea.] These are small spiders, with the abdomen extended back half its length beyond the spinnerets, brightly colored, flattened above, and furnished with several pairs of pointed processes. The cephalothorax is longer than in Epeira and Argiope and widest in the middle. The legs are slender and have only fine and soft hairs. The webs (fig. 437) are inclined and have a hole in the middle surrounded by several turns of smooth thread; when hanging in it the spiders look like burrs or seeds. At a slight alarm they will sometimes drop to the ground and hide under the nearest shelter. [Illustration: FIG. 438. Acrosoma mitrata, enlarged four times.]