with Descriptions of New Forms. 131 



median line divides the thorax, which may denote the line of 

 rupture of the integument in moulting and also that the part 

 preserved is here, as in most instances, the cast-off integument. 

 This line is, however, not more marked than that on the thorax 

 of some living nymphs, resulting from the union of the lateral 

 halves of the terga, and the line along which the break ulti- 

 mately occurs at the time of moulting. The femur, tibia, and 

 tarsus of the first leg on the right side are preserved. The 

 femur is smooth and of about the same length as the tibia. 

 The tibia, on the contrary, is strongly spinous. The first joint 

 of the tarsus is comparatively long; the others are short. 

 The number of -joints in the tarsus can not be made out. The 

 left leg of the third pair shows most of the coxa, the tro- 

 chanter, the femur, and part of the tibia. The femur is stouter 

 than that of the first pair of legs and is likewise smooth. The 

 tibia is slender and preserves the bases of the spines. The 

 trochanter of this leg, also, is seen as a triangular piece uniting 

 the femur and coxa. As in other cockroaches, a progressive 

 rounding during growth of the posterior border of the prono- 

 tum is evident, which gives the pronotum of the adult a circu- 

 lar form. The thin texture and the ornamentation of the 

 pronotum are characteristic and serve to confirm the connection 

 of the nymphs and adults. 



The restoration given here (Figure 15), is based on the sev- 

 eral nymphs of the species and the adult 16 

 which served as the type specimen, the pro- 

 notum of which, more completely uncovered, 

 is here refigured (Figure 1 6). The cockroach 

 is represented in the resting position. Spines 

 have not been observed on the femur. 

 That the tibia is spinous is shown, however, 

 in Figure 1-1. The ovipositor of F. mazona 

 was apparently of medium length. At the 

 time the restoration given by Professor Figure 16. — Pro- 

 Scudder was made (Mem. Boston Soc, vol. notum of adult of E. 

 iii, pi. x, 1882), the presence of the oviposi- mazona - x 2 - 

 tor and the spinous character of the tibia were unknown. 



Formation and Locality. — Coal Measures, Mazon Creek, 

 Illinois. 



Etoblattina juvenis sp. nov. Text-figures 1*7-21. 



The most common nymph at the Lawrence locality is a 

 species with large broad abdomen, the terga having well-devel- 

 oped free edges, and the sterna, rounded corners. Two instruc- 

 tive individuals of this species, lying on a small slab, are shown 

 in their relative positions in Figure 17. The dorsal integument 

 of the nymph at the right of the figure has split down the 



