666 



CLASS IV. INSECTA. 



in no case do they have wings. These organs appear later and 

 increase in size with each successive moult. 



Sub.-Order 1. CURSORIA. 



Hind-legs differing but little from the others. This sub-order consists of 

 five very divergent families with no intermediate forms. 



Fam. 1. Forfieulidae.* The earwigs have short tegmina: the second 

 pair of wings are first folded like a fan, and then folded into four like 

 a piece of note-paper. The cerci have the form of stout forceps which 

 assist in folding the wings, and arise from an eleventh abdominal segment 

 in the embryo. Wingless forms are frequent. The genital orifice is 

 double in the males of some species. In Forficula f L. (Fig. 418) the first 

 abdominal tergum tends to fuse with the thorax ; there is a similar but 

 much more complete fusion in the Hymenoptera. F. auricularia L. (British) 

 is the common earwig ; it is largely carnivorous, eating insects and snails, 



and probably the injury it does 

 to plants has been exaggerated, 

 though it undoubtedly dis- 

 figures many flowers by nib- 

 bling the petals. The female 

 guards her eggs but takes no 

 interest in the young when 

 they are hatched. Chelidura 

 pubescens, also British, is 

 apterous. Traces of tegmina 

 appear in Anisolabis Fieber, of 

 which genus A. maritima and 

 A. annulipes are, British. Ane- 

 chura Scudd. ; Labidura Leach, 

 L. riparia is British ; Labia 

 Leach, a genus often seen in 

 flight ; L. minor is British, as 

 also Apterygida albipennis and A. arachidis. Psalis Serv. is the largest 

 form. 



Fam. 2. Hemimeridae.+ A small family of blind and wingless Insects 

 whose young develop in an extraordinary manner within the body of the 

 mother. The cerci are long and flexible, not jointed. The few species 

 known are external parasites on small mammals. Hemimerus hanseni 

 is West African, living on the body of Cricetomys, a small rodent. The 

 mouth-parts are remarkable, and include a pair of structures, one on 

 either side of the hypopharynx, considered to be reduced maxillulae. 



Fam. 3. Blattidae. Head bent down and in this position invisible 

 from above, body oval and flattened. Coxae large, free, covering sterna 

 of thorax. Tegmina variable in form or absent. Running Insects, with 



* This family is regarded by some entomologists as an Order and named 

 by some the Dermaptera and by others the Euplexoptera. 



| Das Thierreih, 11 Lieferung, Forficulidae and Hemimeridae, de 

 Bormans and Krauss, 1900 ; and British Orthoptera, Naturalist Journal 

 and Guide, Huddersfield, 1897, M. Burr. 



J H. de Saussure, Spic. Ent. Genev., i, 1879 ; also H. J. Hansen, Ent. 

 Tidskr., xv, 1894, p. 65. 



R. Shelford, Trans. Ent. Soc., London, 1906, p. 231. 



FIG. 419. Hemimerus talpoides. Africa. (After 

 de Saussure). A upper, B under surface. 



