ABSTRACT
The terrestrial mermithids include species with a size from a few to 405 mm. The intraspecific variability of the body size of terrestrial mermithids is also extraordinarily large. Most of the terrestrial species characteristically show two overlapping spirally arranged layers of giant fibers in the outer layers of the cuticule. The number of stichocytes is not known for all the terrestrial genera but usually there are 16. Special studies on the species spectrum of mermithids in different biotypes are extremely rare for terrestrial forms of these nematodes, with the exception of such early reports as that of Hagmeier. As even so-called terrestrial mermithids cannot survive longer dry periods, their occurrence in deserts or semiarid regions is virtually out of the question or limited to a few moist spots. Terrestrial mermithids often have only slight host specificity and in addition to their main hosts can occasionally use other insects as food supply, which offer feeding potential varying with their size.
