1878. 



In America, too, in consequence chiefly of the impetus given to 

 the investigation of the subject by the indefatigable Mr. Scudder, 

 discoveries of fossil insects are almost daily being made by members 

 of the United States Greological Survey. 



There can be no doubt that when Geologists are more fully awake 

 to the important deductions to be drawn from an examination of 

 fossil insects, and a comparison of their geographical distribution with 

 that of living species, the remains of this class of the animal kingdom 

 will be more generally sought for and attentively studied. 



Not only is this branch of Palaeontology of interest and import- 

 ance to the Greologist, but to the Zoologist also, as throwing some light 

 on the question of the origin and development of insects ; the com- 

 parative antiquity of the several orders, and their families and genera ; 

 the respective dates of their apparition on the geological horizon ; and 

 the affinities existing between living and extinct species. 



Before proceeding to show how little direct evidence has as yet 

 been furnished, by Palseontological researches, in support of the theory 

 of the evolution of insects from some primitive types, it will be 

 necessary to refer briefly to the opinions on this point of Professor 

 H^ckel and Dr. Fritz Miiller. 



In the opinion of Haeckel, the Insecta^ AracJinida, Ilyriopoda, and 

 Crustacea must have had a common ancestor. The Zoea or Zoepoda, 

 which Haeckel supposes to have been the ancestral form of the 

 Crustacea, are believed by him to have flourished early in the Silurian 

 period, and he thinks that it was probably about the Devonian epoch 

 that certain Zoejpods were naturally selected for a terrestrial life, de- 

 veloped trachese, and became Protracheata, or progenitors of all the 

 great tracheiferous group of the Arthropoda ; whilst those which 

 remained in the water were the ancestors of the branchiferous forms, 

 such as crabs, lobsters, and shrimps. Dr. Pritz Miiller* also is of 

 opinion that the water-inhabiting and water-breathing Crustacea must 

 be regarded as the orginal stem from which the other terrestrial 

 classes, with their tracheal respiration, have branched off. 



It is hardly just to these distinguished Naturalists to refer to their 

 opinions in so cursory a manner ; but my excuse for doing so is that 

 it is not within the scope of this paper to discuss the question of the 

 probable origin of insects, but merely to call attention to some of the 

 facts bearing on the subject which have been gathered from Palaeon- 



* " Facts for Darwin," translated from the German of Fritz Miiller, by W. S. Dallas, F.L.S., 

 ch. xi, p. ] 20. 



