with Descriptions of New Forms. 221 



The most distinctive character of this genus of huge cock- 

 roaches is the large, nearly rectangular pronotum, broadest 

 at the base^ and with sides and anterior border slightly 

 emarginate. The abdomen is seen indistinctly through the 

 wings ; it is large and indicates a bulky body. The length 

 from the front of the pronotum to the tip of the wing is 9 cm , 

 making this probably the largest cockroach known. The tips 

 only of the hind wings are seen. Apparently they are of 

 about the same extent as the front wings. The large hind wing 

 from the same locality, described as Blattina sp. by Scudcler, 

 is here provisionally referred to this species. If this reference 

 is correct, the hind wings are very broad, with much rounded 

 inner border. 



The half-tone illustration accompanying the original descrip- 

 tion of the species was made from the mould of the dorsal 

 surface. The figure given here is taken from the counterpart, 

 in which the outline of the abdomen is more distinct. The 

 two pairs of wings considerably overlap the broa'd abdomen. 

 The life-size restoration is made from the specimen figured. 

 The antennae and legs are reconstructed from related genera. 

 The position adopted is based upon an instantaneous photo- 

 graph taken for this purpose, of the common oriental cock- 

 roach, while running. As represented in the restoration the 

 first leg on the left side has just been thrown out in front, 

 the second on the right side is in motion, while the third on 

 the left is just ready to be drawn forward. The other set of 

 three are, for the instant, supporting the weight of the body. 

 It is not known whether the tibiae of the genus are supplied 

 with spines. These features are, therefore, omitted from the 

 restoration (Figure 32). 



Formation and Locality. — Coal Measures, Mazon Creek, 

 Illinois. Type in the Yale University Museum. 



Hind Wings not in connection with Front Wings. 



The difficulties of nomenclature met with in the systematic 

 treatment of the nymphs of fossil cockroaches are again 

 encountered in dealing with such detached hind wings as lack 

 sufficient characters to identify them with their res}3ective 

 front wings. Several well-marked types of hind wings, pre- 

 sumably representing at least as many species, have been 

 recognized in the collections studied, three of which can be 

 identified with the front wings. The hind wings of Spiloblat- 

 tina maledicta have been described above in connection with the 

 tegmina of that species. The hind wing of Promylacris rigida 

 (Figure 36) is taken from the type specimen (No. 38045, U. S. 

 Kat. Mus.). It is of special interest as revealing the form and 



