with Descriptions of New Forms. 129 



Figure 14. — A nymph approaching maturity. 



Figure 15. — Restoration of Etoblattina mazona Scudder, based upon 

 the type specimen, the wings and pronotum of which are well preserved, 

 and also upon the several nymphs now known preserving practically all parts 

 of the body. 



Figures 10-12, x3 ; Figure 15. natural size; all others, x2. All are from 

 the Coal Measures of Mazon Creek, Illinois. Original of Figure 14 in the 

 National Museum ; all others in the Yale University Museum. 



Scudder' s species Mylacris elongata is based on the close agree- 

 ment in the shape and venation of the tegmina. The con- 

 nection between nymph and adult is inferred from the relative 

 proportion in size between the thorax and abdomen, the large 

 wings already evident in the nymph, and the similar boxlike 

 shape of the body. 



Formation and Locality. — Coal Measures, Mazon Creek, 

 Illinois. 



Mylacris anceps sp. no v. Text-figure 5. 



The specific name M. anceps is proposed for the nymph 

 illustrated in Figure 5, which can not at present be referred to 

 its proper adult species. The most marked characters of the 

 species are its long abdomen and short wings as compared 

 with the species just described. The wings are unusually short 

 considering the size of the nymph. The abdomen is almost 

 or quite as long as the thorax, narrowly elliptical in outline, 

 broadest at the fourth or fifth segment, sloping gradually to 

 the tenth. The tenth tergum is small, and, as in the last spe- 

 cies, apparently consolidated with the ninth, the union being 

 strengthened by a strong ridge running down the center. The 

 cerci in this species are also directed at right angles to the axis 

 of the body. The adults will probably be found to have a 

 proportionately broad and long abdomen. 



Formation and Locality. — Coal Measures, Mazon Creek, Illi- 

 nois. Type specimen in the Yale University Museum. 



Blattinaei^:. 



Etoblattina. 

 Scudder, Mem. Boston Soc. Nat. Hist., vol. iii, p. 56, 1879. 



Etoblattina mazona. Text-figures 10-16 ; and Plate I, Figure 2. 

 Scudder, Proc. Boston Soc. Nat. Hist., vol. xxi, p. 391, 1882. 



Etoblattina mazona is at present the most completely known 

 paleozoic cockroach. A rather full description will therefore 

 be given of several individuals representing stages in the de- 

 velopment of the species. A restoration of the species as 

 now known is also attempted. The smallest specimen seen is 

 15 ram long. The body is slender and the two wings appear as 



Am. Jour. Scl— Fourth Series, Vol. XVIII, No. 104.— August, 1904. 

 9 



