6 Annals Entomological Society of America [Vol. X, 



judging from the plants, would refer the beds to the Carbonif- 

 erous, even later than the Mississippian. Leaving these matters 

 undecided, there are still some important facts which admit of 

 no dispute. In the first place, the insects, like the higher 

 flowering plants, first appear on the scene in a highly developed 

 condition. It is true that the Palasodi.ctyoptera are very 

 primitive as compared with our modern Lepidoptera, Hymen- 

 optera or Coleoptera, but in their own particular line, they 

 represented a wonderful development of insect life.* There 

 was evidently great variety of form and structure, while many 

 of the species reached an enormous size. The anterior wings of 

 ArchcBoptilus gaullei Meunier are estimated to be 18 cm. long, 

 and as the distance between the wings is 24 mm., the total 

 expanse is 384 mm. — over 15 inches. f Truly, there were giants 

 in those days! This exuberant type flourished during a period 

 before the rise of the Blattids, but extended into the Pennsylva- 

 nian, where, as at Mazon Creek, Illinois, it is accompanied by 

 a rich fauna of Protorthoptera and Blattoids. It existed 

 equally in Europe and North America, and in both areas 

 gradually disappeared during the Upper Carboniferous or 

 Pennsylvanian. The disappearance of the Palaeodictyoptera is 

 coincident with the rise of the Blattoids; and in America, at 

 least, we soon come to a period when the Blattoids were dom- 

 inant, to the total exclusion of Palaeodictyoptera, and the great 

 reduction of all other insects. This lasts to the end of the 

 Pennsylvanian, and perhaps into the Permian; but in the 

 Permian strata of Kansas, in which Sellards obtained a very 

 rich insect fauna, Blattoids are in the minority, and other 

 insects are numerous. Thus we have certainly three great 

 periods, so far as the insects are concerned; one prior to the 

 appearance of Blattoids, one during which the Blattoids and 

 Palasodictyoptera and Protorthoptera existed together, and one 

 during which the Blattoids were dominant almost to the 



*Reconstructions of these insects must not be taken too seriously. In his 

 very valuable and suggestive paper on the Ancestry of Insects (Am. Jn. Sci., 

 Nov., 1916), Mr. J. D. Tothill copies a couple of figures from Handlirsch, which 

 that author states to be diagrammatic reconstructions. Mr. Tothill, however, 

 makes Handlirsch's hypothetical and reconstructed Palseodictyopteran larva a 

 Stenodiclya, and proceeds to discuss the larva of that genus, as if it were well 

 known. 



fThe largest known insect, Meganeura monyi Brongniart, from the Upper 

 Carboniferous of Commentary, France, is stated to have had an expanse of fully 

 70 cm., or about 2 ft. 4 inches. Handlirsch refers it to the Protodonata, a type 

 prophetic of our modern dragon-flies. 



