INTRODUCTION. 3 



continent generally, and from the United States, overshadowed the limited British 

 series, which seemed almost trivial by comparison. The present monograph shows, 

 however, that the fossil insect-remains of the British Coal Measures are far more 

 abundant than was supposed, and that they are by no means unimportant. About 

 seventy specimens are known, of about sixty species, and they represent five of 

 the great groups of fossil insects. 



Paheodietyoptera are the dominant forms, and are closely followed by Blattoids, 

 several of which are referable to genera occurring in the French and Belgian 

 coalfields. The British examples of Soomylacris are represented near Lens and 

 Lievin by Soomylacris lievinensis, IV., while Phylomylacris mantidioides has its 

 counterparts in Phylomylacris godoni, Pr., and PJnjlomylacris lafittei, Pr., from Lens. 

 The great Protodonata of Commentry are represented in the Bristol coalfield by 

 Bolton it ex radstoclcensis. 



The generic identity of French and British Coal Measure insects implies that 

 they formed part of a general and wide-spread fauna, a view which is strengthened 

 by the fact that while Soomylacris deanensis and S. stocki occur in the Forest of 

 Dean coalfield, to the west, S. burri occurs in the Kent coalfield to the east, and 

 only separated by the Straits of Dover from the Coal Measures of Northern 

 France, in which Pruvost finds other species of the same genus. 



Pruvost has also shown that in the Coal Measures of Lens and Lievin there is 

 present a well-defined horizon of Anthracomya phillipsii, in which that species 

 passes through the same developmental changes as in the Kent coalfield. 



It is extremely likely that the Kent coalfield will later yield numerous insect- 

 remains closely allied to those of France, and that systematic search will amplify 

 the list of forms already known from all the British coalfields. 



The British Palaeodictyoptera, on the whole, are more varied than the French, 

 few forms showing the primitive condition of Stenodictya, while certain examples, 

 such as Mecynoptera hibercidata, Palaeomantis macroptera, and the three genera of 

 Lithomantids, are highly specialised. A similar degree of specialisation is seen in 

 the British examples of the Protorthoptera, while the Blattoids, by their numerous 

 genera and species, indicate that the group had a long history and a wide 

 geographical range in the British coal period. 



The fossil insects already found in the British Coal Measures form probably 

 but a small fraction of those which remain to be discovered when attention is more 

 fully directed to them. The insect-fauna, however, is not usually associated with 

 the general fauna in the Coal Measures, but occurs in beds of lighter coloured rock 

 than the ordinary carbonaceous shales, and with abundant ironstone nodules, or in 

 the case of the Blattoids, in association with masses of drifted vegetation in the 

 black shales, where the neuration of the wings so closely simulates the pinnules of 

 Neuropteris as to be mistaken for the latter and cast aside. 



While insect-remains are usually regarded as wholly restricted to the West- 



