10 FOSSIL INSECTS OF THE BRITISH COAL MEASURES. 



We shall not be far wrong in assuming that the larvae of some of the Coal 

 Measure insects were wholly aquatic, others semi-aquatic ; that the adult Blattoids 

 were indifferently aquatic or terrestrial; the adults of the non-Blattoid types spent 

 most of their life in the vicinity of the swamp-pools in which their larval stages 

 were passed, and to which they might need to return to lay their eggs. 



Such a view seems to accord with the known facts, and will explain the special 

 character of the fauna of such deposits as those of Coseley, in Staffordshire, and 

 the brick-clays of Sparth Bottoms, Rochdale, Lancashire. These are evidently 

 true lagoon or swamp-pool deposits as contrasted with the ordinary shales and 

 binds of the Coal Measures. 



FOOD OF COAL MEASURE INSECTS. 



The nature of the food of Coal Measure insects has been much discussed, as it 

 is so closely associated with habits. Ilandlirsch considers that the Gymnosperms 

 and Pteridosperms of the Coal Measure forests were not likely to have been 

 frequented by insects in search of food, as these plants do not prove attractive to 

 living insects. Pruvost, on the other hand (1910,? 1020, " La Faune Continental 

 du Terrain Houiller du Nord de la France," 'Mem. Carte Geol. France,' pp. 266 — 

 267), considers that many members of the Coal Measure flora possessed in their 

 spores, or in the case of the higher plants, in their cones, a plentiful food supply for 

 insects, and he finds in the association of a Phylloblatta at Lens with the Potonica 

 of Linopteris some support for his conclusions. 



The contemporaneous rapid development of plants and insects is also quoted 

 by Pruvost in support of his views. 



Several writers have argued that the powerful wings and consequent powers 

 of rapid flight of many of the insects are more in accordance with a predatory and 

 carnivorous habit than with a purely frugivorous or herbivorous one, and this 

 belief has led Lameere to write as follows (1917, ' Bull. Soc. Zool. France,' vol. xlii, 

 pp. 36 — 37) : "Over the lake of Commentry flew magnificent Ephemeroptera and 

 splendid Odonatoptera, the carnivorous larvae of which were aquatic; doubtless 

 the Odonatoptera, when fully grown, devoured the Ephemeroptera, of which the 

 most fully developed types, the Megasecopterithe, which have left no descendants, 

 must have made great slaughter among the smaller insects. 



" On the ground, in the forests, swarmed innumerable Blattoids, which 

 frequented the detritus, and which had as enemies the ferocious and agile 

 Orthoptera, the varied counterparts of our Mantidae. These latter must have 

 attacked equally the large vegetarian Orthoptera, the counterparts of the Phasnue, 

 which probably climbed on trees, and the bulky Protohemiptera, which sucked the 

 sap. Some of the Orthoptera jumped, and there were some which by their 

 appearance recall our Acridians, but all these beings were mute. 



