Scudder’s Fossil Insects of North America. 489 
(4.) Nearly all are synthetic types of a comparatively narrow 
range. 
(5.) Nearly all bear marks of affinity to the Carboniferous paleo- 
ictyoptera. 
(6.) On the other hand, they are often of more and not less com- 
licated structure than most paleeodictoptera. 
(7.) With one exception, they bear little special relation to Car- 
beniferous forms, having a distinct facies of their own. 
(8.) The Devonain insects were of great size, had membranous 
wings and were probably aquatic in early life. 
(9.) Some of the Devonian insects are evidently precursors of 
existing forms while others seem to have left no trace. 
(10.) They show a remarkable variety of structure indicating an 
abundance of insect life at that epoch. 
(11.) The Devonian insects also differ remarkably from all other 
known types, ancient or modern ; and some of them appear to be 
even more complicated than their nearest living allies. 
(12.) We appear, therefore, to be no nearer the beginning of 
things in the Devonian epoch, than in the carboniferous so far as 
-either greater unity or simplicity of structure is concerned. 
(13.) Finally, where there are some forms which tosome degree bear 
out the general derivative hypothesis of structural development, 
there are quite as many which are altogether unexpected, and can- 
not be explained by that theory, without involving suppositions for 
which no facts can at present be adduced.” 
Sir William Dawson’s note is entitled : ‘‘ Note on the Geological 
relations of the Fossil Insects from the Devonian of New Bruns- 
wick,” in which a section of the rocks taken at the ‘‘ Fern ledges” is 
presented and no less than eight * plant-beds” are enumerated and 
the various forms found in each recorded—the total thickness of the 
beds embraced in this section ‘‘ being” 440 feet, 11 inches. 
FosstL COCKROACHES. 
Then comes ‘‘ The species of Mylacris, a Carboniferous genus of 
Cockroaches” with reference to a form described from the coal 
measure of Sydney, Cape Breton under the following designation :— 
1. Mylaeris Bretonense, Scudder. The other paleeozoic cock- 
roaches known from Canadian rocks were described by the same 
author in a preceding chapter, viz : ‘‘ Paleeozoic cockroaches, a com- 
plete revision of the species of both worlds, with an essay toward 
their classification.” These are described in the monograph, pp. 
43-154, and are from the Acadian coal field. They include 
Sydney, Cape Breton, 
1. Mylacris Bretonense, Scudder. 
2 oy Heeri, Scudder. 
3. Petroblattina sepulta, Scudder. 6 
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