56 John Henry Comstock 



paleozoic insects, but a common simple type of venation 



which barely admitted of family divisions." * 



In his classification of the Palseodictyoptera.f Mr. Scudder 



indicates a number of these family divisions, and groups them 



according to their general facies and by their relationship to 



succeeding types into four sections as shown by the following 



table.! 



Pai^^odictyoptera. 

 Orthopteroidea. 



1. Fam, Palceoblaitariw . 

 Subf. Mylacrida 

 Subf. Blattinaricg. 



2. Fam. Protophasmida. 

 Neuropteroidea. 



1. Fam. PalephemeridcE. 



2. Fam. Homothetidce. 



3. Fam. PalcEopterina. 



4. Fam. Xenoneuridce. 



5. Fam. Hemeristina. 



6. Fam. Gerarina. 

 Hemipteroidea. 



Eugereon, Fulgorina, Phthanocoris. 

 Coleopteroidea. 



Borings supposed to be of beetle-like insects. 



It is evident from a study of the fossil remains that our 

 knowledge of the primitive Palaeodictyoptera is very frag- 

 mentary. The few forms that have been discovered in the 

 Silurian and devonian rocks are evidently more highly special- 

 ized than certain other forms which have been found in the 

 carboniferous ; the most generalized wings known to us, as I 

 .shall show later, being from this epoch. We must, therefore, 

 turn to the carboniferous as the earliest epoch from which we 

 have data to base our conclusions regarding the structure of 

 the primitive insect wings. 



As this is a comparatively late period we are forced to pur- 

 sue practically the same method that we would were we to at- 

 tempt to solve the problem by a study of living insects. That 



* Scudder. Pretertiary Insects p. 319, 320. 



t Zittle Traite de Paleontologie t. II. and in Bull. U. S. Geol. Survey 

 No. 31. 



X It would be presumptuous for one who has studied the paleozoic in- 

 sects so little as I have done to criticise the accepted classification of 

 them. I therefore quote it without change, although it does seem to 

 me that ordinal distinctions arose earlier than indicated by Mr. Scudder. 



