812 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXIX. 



Hapalopteroidea, Mixotermitoidea, Protorthoptera, and Protoblat- 

 toidea), which I regard a.s connecting- links between the Paleodictj^op- 

 tera and modern insect groups, and which ma}' be designated 

 tra)tx!t!<mal groups, appear hiter than their conjectural ancestors, 

 attain their maxinuun in the middle beds, and with the close of the 

 Paleozoic again vanish. It follows tinally that the single modern 

 order, thus far found in the An)erican Paleozoic, the Phittoidea. lirst 

 makes its appearance toward the middle of this period and continues 

 with progressive increase to the close. 



The following table should make clear the fact last mentioned: 



I 



