2 BRITISH ORTHOPTERA. 



Orthoptera as an Order of Insects worthy of study is 

 the fact that, leaving out the Protura, Zoraptera, 

 Collembola, Campodeioidea, and Thysanura, this Order 

 probably contains the oldest insects which have sur- 

 vived to the present geologic age. 



In support of this statement it is sufficient here 

 to point to their geologic record, the slight post- 

 embryonic development which they display, the fre- 

 quent absence or rudimentary condition of the elytra 

 and wings, and the mandibulate mouth. Another 

 point testifying apparently to the antiquity of the 

 Order is the presence of cerci resembling posterior 

 antennae, and no doubt in some cases useful as such- 

 throughout the British species. These cerci are very 

 characteristic of the apterous insect Campodea stapJii/- 

 linus (Plate I, fig. 1), which may, or may not, be an 

 extremely primitive insect come down to our time y 

 but at any rate is of an early type.* This simple 

 insect calls to mind a newly-hatched and therefore 

 wingless earwig (PI. I, fig. 2) in which the callipers 

 (cerci) are proportionately much longer and simpler 

 than thev are in the imao'o.f It should be noticed 



/ <~> 



that they are present also in other ancient Orders, 

 such as the Plecoptera, Odonata, and Ephemeroptera. 

 Probably 10,000 species, which has been given as 

 an estimate of the total number of Orthoptera living 

 at the present day, is a very modest guess. About 

 500 are inhabitants of Europe, while of those which 

 may reasonably be considered British, there is an 

 interesting group containing the rather small total of 

 39 species, only a few of which extend their range 

 into Scotland. Not even all of these 39 can be looked 

 upon as indigenous, though such as are not are so far 

 naturalised as to breed here and thus establish their 



* See ' Origin and Metamorphose s of Insects/ by the Right Hon. Lord 

 Avebury, 1902. 



t C. J. Gahan's recent detection of joints in the callipers of an embry- 

 onic earwig, and their presence in the nymph of a Ceylon earwig, Dyscritina, 

 longisetosa, Westw. (- gerstteckeri Dohrii), investigated by E. E. Green, 

 strengthen this conclusion. See 'Trans. Ent. Soc. Lond./ 16 Mar. 1898; 

 and Burr's " Dermaptera," in ' Fauna of British India/ p. 11, 1910. 



