Afterwards Haeckel in his "Generelle Morphologie" (1866) and "History of Creation," published in 1868, reiterates the notion that the insects are derived from the larva (Zoea, Fig. 190) of the crabs, though he is doubtful whether they did not originate directly from the worms.[16] It may be said in opposition to the view that the insects came originally from the same early crustacean resembling the larva of a crab or shrimp, that the differences between the two types are too great, or, in other words, the homologies of the two classes too remote,[17] and the two types are each too specialized to lead us to suppose that one was derived from the other. Moreover, we find through the researches of Messrs. Hartt and Scudder that there were highly developed insects, such as May flies, grasshoppers, etc., in the Devonian rocks of New Brunswick, leading us to expect the discovery of low insects even in the Upper Silurian rocks. At any rate this discovery pushes back the origin of insects beyond a time when there were true Zoeae, as the shrimps and their allies are not actually known to exist so far back as the Silurian, not having as yet been found below the coal measures. The view that the insects were derived from a Zoea was also sustained by Friedrich Brauer, the distinguished entomologist of Vienna, in a paper[18] read in March, 1869. Following the suggestion of Fritz Mueller and Haeckel, he derives the ancestry of insects from the Zoea of crabs and shrimps. However, he regards the Podurids as the more immediate ancestors of the true insects, selecting Campodea as the type of such an ancestral form, remarking that the "Campodea-stage has for the Insects and Myriopods the same value as the Zoea for the Crustacea." He says nothing regarding the spiders and mites.