The coriaceous leaves of sclerophyllous plants also, to some extent, are similarly protective.
The entire valley of the Rio Grande, from El Paso to Brownsville, grows many species of cactus, and other prickly coriaceous shrubs.
Again, the accuracy of the statement that the fleshy Agaricini, Polyporei, Pezizae, &c., are relatively rarer in the tropics may depend on the fact that they are more difficult to collect and remit for identification than the abundantly recorded woody and coriaceous forms of these regions.
The adult insect has a coriaceous scutellum, rugulose apically, usually without a shallow medial depression.
In the Argasidae the anterior portion of the dorsal surface of the body is extended forwards above the capitulum, so that this structure is concealed from above; the integument is fairly uniformly granular or coriaceous above and below; the palpi are simple and unmodified; there is no sucker beneath the claws in the adult, and there is only a slight structural difference between the sexes.