PROCEEDINGS. 1917 • 25 



primeval creatures formed a single group of generalized Hexapods. 

 Brauer on the other hand — also quoted by Sharp (8) — considers that 

 these earlier forms can be relegated to families existing today and form- 

 ing parts of the Orthoptera, Neuroptera and Hemiptera. Since it is 

 chiefly the wings of these forms that have been found, it would seem 

 arbitrary to assign the species to a separate order, said to be extinct, on 

 merely alar evidence. The fact that there is one species, Eugereon 

 bockingi, with head and mouth parts of a hemipterous or dipterous 

 nature while the wings are distinctly neuropetrous. seems to us to 

 weaken Scudder's position. 



In the more recent rocks, insect remains become comparatively 

 numerous, and in Mesozoic strata forms that can be satisfactorily 

 referred to existing orders are found, the Palaeodictyoptera of Golden- 

 berg and Scudder having disappeared. The Blattidae do not apparently 

 present any great discontinuity between their Palaeozoic and Mesozoic 

 forms. It would be well to remark here that the history of the cock- 

 roaches is the best preserved in the rocks, of any insect. In the Car- 

 boniferous epoch they existed in considerable numbers and variety, and 

 a still earlier but doubtful fossil has been found in the Silurian of 

 Calvados. It is curious to note, accordiupf to Brongniart (6), that some 

 of the females of these fossil Blattidae b.ad a well-marked ovipositor, 

 in the shape of an elongate, exserted organ at the end of the body, by 

 means of which the insect may have desposited its eggs in trees and 

 other receptacles in the manner prevailing among Orthoptera of our own 

 times. 



In the strata of the Secondary epoch, remains of Blattidae have also 

 been discovered in both Europe and America, in Oolitic, Liassic and 

 Triassic deposits. From the Tertiary strata, on the other hand, com- 

 paratively few species have been brought to light. A few have been 

 discovered preserved in amber. 



According to Scudder (5, p. 109) not only were insects abundant in the 

 Tertiaries, but their remains indicate conditions of existence very similar 

 to what we find around us today. "Certain peculiarities of secondary 

 sexual dimorphism accompanying special forms of communistic life, 

 such as the neuters and workers in Hymenoptera and the soldiers of the 

 Termitidae, are also found, as would be expected, among the fossils, at 

 least through the whole series of the Tertiaries. The same may be said 

 of other sexual characteristics, such as the stridulating organs of the 

 Orthoptera, and the peculiarities of ovipostion, as seen in the huge egg- 

 capsules of an extinct Sialid of the early Tertiaries. The viviparity of 

 the ancient Aphididae is suggested, according to Buckton, by the appear- 

 ance of one of the specimens from the Oligocene of the Florissant, while 

 some of the more extraordinary forms of parasitism are indicated at a 

 time equally remote by the occurrence in amber of the triangulin larva 



