Coleoptera (beetles), and 8.4% Hemiptera (true bugs). Spiders made up 7.9% of the diet and Cophosaurus were found to occasionally feed on small lizards, particularly ornate tree lizards (Urosaurus ornatus), in the late summer and early spring when hatchling emerged and were abundant. Another study conducted in the Mapimí Biosphere Reserve in Durango, Mexico, found the most frequent prey items were spiders, Hymenoptera, Lepidopteran (caterpillars) adult and nymph Orthoptera, beetles, and true bugs. Less frequent prey identified in these studies included Neuroptera (lacewings, mantidflies, antlions), mites, pseudoscorpions, termites, Homoptera, adult Lepidoptera, and Odonata (dragonflies, damselflies) The Arizona study found that plants made up 5.5% of the diet, while the Durango study found only two cases of plant ingestion and interpret them as accidental intake. The most common, or highest percentage of prey items (e.g. Hymenoptera, caterpillars, etc.) in the diet were found to change annually in the Durango study. Cophosaurus use a sit and wait foraging strategy, often situating themselves on a high vantage point such as a rock, bolder, or fallen limb, in a relatively open space and dashing out to take passing insects. They have been observed leaping into the air or at low hanging vegetation to catch their prey. In one study, months with rain were significantly correlated with an increase of arthropods in the environment and in the dietary intake of the lizards. There was not a significant deference in the diet of males and females. Competition for food between adults and juveniles, as well as other species of sympatric lizards is at least partially alleviated by resource partitioning, determined by differences in body size and jaw length. Habitat The greater earless lizard native to the arid environment of the Chihuahua Desert, extending into western areas of the Tamaulipan mezquital, and the northeastern margins of the Meseta Central matorral, as well as the semi-arid Edwards Plateau and Central Great Plains in Texas, and the Arizona transition zone (between the Sonoran Desert and Arizona Mountains forests) in the west. Within these ecoregions it typically occupies open scrubland and areas of sparse vegetation, with rocks and boulder. Limestone ledges and outcrops near streams with boulders and crevices, and dry gulches, arroyos, and canyons with alluvium deposits of silt, sand, gravel, and rocks are often preferred, but it is not strictly limited to these areas. Gentle to moderate slopes of limestone and gravel and hills of granite and igneous