CARBONIFEROUS COCKROACHES. 415 



the two front wings, slightly pai'ted and vague indications of the thorax and possibly of 

 the legs. The prothorax is quadrate, pinched transversely in the middle to a definite 

 ridge, which is probably accidental. The legs, if the elevations near their position may 

 be taken to indicate their appearance, must have been very short and tolerably slender. 



The front Avings are rather slender, the tip well rounded and slightly jiroduced, the 

 costal margin slightly shouldered at the base, beyond nearly straight in the basal half, 

 apparently sloping downward beyond, the inner margin ajDparently broadly rounded but 

 the basal half not clearly indicated in the specimen. The veins appear to originate from, 

 the middle of the u];)per half of the base of the wing, and have scarcely the least basal ar- 

 cuation. The mediastinal vein runs at but slight distance from and nearly parallel to the 

 costal border, in the outer half or more constantly but very gradually approaching it, emit- 

 ting numerous oblique generally simple branches ; the vein terminates in the middle of the 

 outer half of the wing, and shows no such peculiarities at its tip as characterize the Eu- 

 ropean si^ecies. The scapular vein also is not so peculiar as in O. reticulata; it runs in 

 near proximity and parallel to the mediastinal vein, but there is the same slight bend in 

 its course at the base of the principal branch; the mass of the branches, which are much 

 fewer than in O. reticulata, do not arise as there from a vein emitted abruptly from near 

 the base of the second branch, to which they are inferior, but from the principal branch 

 itself, to which they are superior. Less can be said about the other veins, as they are ob- 

 scured throughout most of their course, but the internomedian vein tei-minates at about 

 the end of the middle third of the wing and has only few branches; and the externome- 

 dian branches all terminate on the inner margin. 



The wing is 19 mm. long, and 7 mm. broad, the breadth to the length being as 1 : 2.7, 

 It is reticulated minutely, as in the European species, and is interesting as being the second 

 species of the genus known, and as illustrating once more the close relationship of the 

 insect fauna of Eiu'ope and America in carboniferous times. It is a smaller and slenderer 

 species than the European. 



It comes from the beds of Mazon Creek, Illinois, and was sent to me by Mr. R. D. Lacoe, 

 in whose collection it bears the number 2039. 



EXPLANATION OF PLATES. 

 Plate 31. 

 Figs. 1-4 by Mrs. Katherine Peirson Ramsay ; fig. 5 Ijy J. S. Kingsley ; figs. G-7 by J. II. Emerton. 

 Fig. 1. Promylacris ovalis, f cast. 

 " 2. Promylacris ovalis, ; side view. 



" 3. Fromylacris ovalis, f cross section of prothorax in middle. 

 " 4. Fromylacris ovalis, -} relief. 

 " 5. Archimylacris paucinervis. \ 

 " G. Fromylacris rigida. } 

 " 7. Faromylacris ampla. f 



Plate 32. 

 Figs. 1-2 by J. S. Kingsley ; figs. 3-4 by Mrs. Katherine Peirson Ramsay ; fig. 5 by S. H. Scudder ; fig. G by J. Henry Blake. 

 Fig. 1. Faromylacris rotunda ; t cross section of thorax in middle. 

 " 2. Faromylacris rotunda, f 

 " 3. Oryctohlattina occidua. ^ 

 " 4. Etohlattina occidentalis. f 

 " 5. Liihomylacris pavperata. f 

 " C. Promylacris testudo. ^ 



