with Descriptions of New Forms. 121 



figured for Locusta by Dewitz.* From this specimen it 

 appears that the ovipositor is composed of probably three 

 pairs, of which the inner is the smallest. In the later stages 

 when the three pairs have become united the component parts 

 are indicated by a groove down the center (Figure 13). 



Cerci. — The cerci, which are not uncommonly preserved, 

 vary a good deal in length in the different genera and species, 

 from very long as in Etoblattina juvenis to a moderate length 

 as in E. mazona and other species. Usually the cerci are 

 directed obliquely to the body ; occasionally, however, they 

 stand at right angles, as in Mylacris ancejps. 



Development. — The development, as shown by the numerous 

 nymphs of the collections representing various stages in the 

 ontogeny of single species, is, as in modern cockroaches and 

 other Orthoptera, direct, the young resembling the adults and 

 growth taking place by a succession of moults. 



Classification and Description of Carboniferous Cockroaches. 



Order Orthoptera. 



The Carboniferous cockroaches are quite generally recognized 

 as constituting a group of family rank, the Paleoblattidse, in 

 contradistinction to the modern family Blattidae. In the dis- 

 position of the Paleoblattidse under the larger divisions, there 

 is, unfortunately, no such uniformity of usage. They are, by 

 some, separated entirely from their modern descendants and 

 included along with other insects in a distinct order, the Paleo- 

 clictyoptera. By others they are referred directly to the 

 Orthoptera. This diversity of classification, affecting all the 

 paleozoic insects, results not so much, perhaps, from any dis- 

 agreement as to the essential facts presented, so far, at least, 

 as cockroaches are concerned, as from a difference in the view- 

 point from which the facts are interpreted and applied. 



The chief contention for the establishment of the order 

 Paleodictyoptera, as expressed by Professor Samuel H. Scud- 

 der, is that paleozoic insects as a whole are more closely related 

 among themselves than to their (known) descendants of meso- 

 zoic and later times, — a classification in which emphasis is 

 given to the interrelation of contemporaneous but diverging 

 groups, or the lateral relation of organisms, rather than to the 

 lineal or phylogenetic relation in time of particular lines of 

 development. The question of the classification of paleozoic 

 insects in general is not within the range of this paper and will 

 not be touched upon here, except in so far as the principles 

 applied affect the disposition of the Orthoptera as represented 

 by the cockroaches. The gap between the Carboniferous 

 *Zeit. fur wiss. Zool., vol. 25, p. 176, pi. 12, figs. 1-11, 1875. 



