312 Sellards — Structural Characters of Cockroaches. 



Etoblattina mazona (to be figured later) have apparently not 

 yet united and present a striking resemblance to the early 

 stages in the development of the ovipositors of the Locustidae, 

 as 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 later stages 

 when the three pairs have become united, the component parts 

 are indicated by a groove down the center (Plate VII, figures 3 

 and 4). 



New Forms. 



A number of new forms have been obtained and are 

 described in manuscript. One of these (Plate VII, figure 6) is 

 remarkable among cockroaches of the Coal Measures, not only 

 for the presence of numerous comparatively strong cross bars 

 in the tegmina, but especially for the course of the anal veins, 

 most of which end on the anal furrow. The latter character 

 has not been previously observed on any member of the Paleo- 

 blattidse, and the former but rarely. 



A new genus from Mazon Creek is of interest because of the 

 shape of the pronotum and the unusual size of the type spe- 

 cies, which is by far the largest known Paleozoic cockroach. 

 The type specimen measures not less than three and one-half 

 inches (9 cm ) from the anterior margin of the pronotum to the 

 tips of the wings. The width of the body including the wings 

 is one and one-half inches. The abdomen is long, thick, and 

 bulky. The pronotum, unlike that of any other described 

 Paleozoic genus, is nearly rectangular in shape, truncated in 

 front, and enlarged and rounded at the base. The lateral mar- 

 gins are not quite parallel. The sides at first converge, but 

 expand at the front border. A median line extends down 

 the center. The wings are longer than the abdomen. The 

 costal border of the front wings is slightly and regularly 

 arched. The type of venation is that characteristic of the 

 tribe Blattinarise. The subcostal area is narrow and extends 

 about two-thirds the length of the wing. Numerous superior 

 veins are given off from the main stem. The radius is strong. 

 A superior branch is given off near the base, and a few others 

 farther out. The median area is small. The cubitus, on the 

 other hand, is well developed, extends to near the inner angle 

 of the wing, and gives off numerous inferior branches. The 

 hind wings, the tips of which are seen, are apparently of about 

 the same length as the front. 



The name Megablattina is suggested for the g enus, and M. 

 Beecheri for the type species (Plate Yft). YlJJi . 



*Zeit. furwiss. Zool., vol. xxv, p. 176, pi. 12, figs. 1-11, 1875. 



