THE ROCK CRAWLERS (GRYLLOBLATTODEA) OF
R. A. Cannings and G. G. E. Scudder
Copyright © 2005 - All rights reserved
Extracted from the forthcoming publication The Insect Families of British Columbia.
Elongate, sub-cylindrical, somewhat flattened, soft-bodied reddish-brown exopterygote insects. The head is prognathous, rather flattened with chewing mouthparts. The compound eyes are more or less reduced, with the ommatidia not contiguous. Ocelli are absent. The antennae are long and filiform, with 28-39 distinct segments.
The thorax lacks wings, and the three thoracic segments are similar and rather separate. The prothorax tends to be the largest thoracic segment, and the pronotum lacks lateral descending lobes. Thoracic sternum is composed of several free sclerites, and has a distinct metathoracic spinea. All legs are relatively long and slender, adapted, for walking with large coxae, the posterior coxae being rather conical. The tarsi are 5-segmented.
The abdomen is free from the thorax, has a relatively large first abdominal sternum that bears an eversible sac. The body terminates in two long, flexible 5-9 segmented cerci. The male has a relatively large ninth sternum, and distinct asymmetrical coxae that bear styli. The male genitalia are asymmetrical. The female, which does not have the eight sternum large and produced into a subgenital plate, has a prominent ovipositor with three pairs of values. This ovipositor is rather sword-shaped and strongly projecting beyond the end of the body.
The terrestrial insects, that lack distinct auditory organs, are active carnivores, that live primarily in cool habitats in the Northern Hemisphere. There is only one family, The Grylloblattidae.
Rock-crawlers are often regarded as "living fossils", because they combine features of several insect orders, namely those of the Blattaria, Dermaptera and Orthoptera. There is much debate about the systematic relationships. The order is sometimes called the Notoptera.
Ando, H. (Ed.) 1982. Biology of the Notoptera. Kashiyo-Insatsu Co. Ltd., Nagano, Japan. 194 pp.
Gurney, A.B. 1948. The taxonomy and distribution of the Grylloblattidae. Proceedings of the Washington Entomological Society 50:86-102.
Kamp, J.W. 1963. New species of Grylloblattodea with an interpretation of their geographical distribution. Annals of the Entomological Society of America 56:53-68.
Kamp, J.W. 1970. The cavernicolous Grylloblattodea of the western United States (1): Annales de Speleology 25:223-230.
Kamp, J.W. 1979. Taxonomy, distribution, and zoogeographic evolution of Grylloblatta in Canada (Insecta: Notoptera). Canadian Entomologist 111:27-38
This write up is extracted from the forthcoming publication by Scudder and Cannings: the Insect Families of British Columbia.
Illustrations by L. L. Lucas. Copyright © 2005 - All rights reserved