580 



INSECTA. 



[PAR. PRO. 



cupy only a slight portion of the lower 

 margin. Type P. vetusta. 



gurleyi, Scudder, 1884, Proc. Amer. 

 Acad. vol. 20, p. 173, Coal Meas. 



lacoana, Scudder, 1884, Proc. Amer. 

 Acad., vol. 20, p. 173, Coal Meas. 



superba, Scudder, 1884, Proc. Amer. 

 Acadl, vol. 20, p. 173, Coal Meas. 



vetusta, Smith, 1871, Am. Jour. Sci. and 



Arts, 3d ser., vol. 1, p. 44, Coal Meas. 

 PAROMYLACRIS, Scudder, 1885, Proc. Acad. 

 Nat, Sci. Phil., p. 35. [Ety. pares, before, 

 or forefather ; Mylakris, a kind of roach.] 

 Body much arched; pronotal shield 

 more than twice as broad as long; 

 wings extremely broad; mediastinal 

 area large and extended, and with the 

 scapular occupying half the wing; ex- 

 terno-median area expanding apically. 

 Typ^ P. rotundum. 



rotundum, Scudder, 1885, Proc. Acad. 



Nat. Sci. Phil., p. 35, Coal Meas. 

 PETRABLATTINA, Scudder, 1876, Can. Geol., 

 vol. 8, p. 88. [Ety. petra, stone ; Blat- 

 tina, a genus.] Scapular and externo- 

 median areas together covering more 

 than half the wing; the externo-median 

 vein directed toward and terminating 

 near the middle of the inner border of 

 the wing, branches superior ; interno- 

 median vein very short. Type P. 

 sepulta. 



sepulta, Scudder, 1876, (Blattina sepulta,) 

 Can. Nat. and Geol., vol. 8, p. 88, Coal 

 Meas. 



PHTHANOCORIS, Scudder, 1884, Proc. Bost. 

 Soc. Nat. Hist., vol. 22, p. 58. [Ety. 

 phthaiw, first ; kore, pupa.] Front wing 

 differentiated from the hind wing; 

 corium distinct from the membrane, 



FIG. 1093. Plangtichnus erraticus. 



narrow clavus ; no embolium or cun- 

 eus ; mediastinal and scapular veins 

 widely separated at base. Type P. oc- 

 cidentalis. 



occidentalis, Scudder, 1884, Proc. Bost. 

 Soc. Nat. Hist., vol. 22, p. 58, and Mem 



FIG. 1094. Platyphemera 

 anticua. 



Bost. Soc. Nat. Hist., vol. 3, p. 348, Coal 



. Meas. 



PLANGTICHNUS, n. gen. [Ety. Plagktos, 

 wandering ; ichnos, track.] A zigzag, 

 half-cylindrical, broken trail, running 

 in any and every direction ; sometimes 

 dotted or sunk deeper at the angles 

 than at other places, or most depressed 

 between the angles in some cases. 

 Supposed to have been made by the 

 larva or pupa of some Palseodictyopter- 

 ous insect. See remarks under Haplo- 

 tichnus. Type P. erraticus. 



erraticus, n. sp. A simple, irregularly 

 zigzag, half-cylindrical, broken trail, 

 running in any and every direction, 

 depressed in spots deeper than the 

 general trail. Collected in the upper 

 part of the Kaskaskia Group at the 

 Whetstone quarries, in Orange County, 

 Indiana. 



PLATEPHEMERA, Scudder, 1867, Can. Nat. 

 and Geol., 

 2d ser., 

 vol. 3, p. 

 202. [Ety. 

 platys, flat ; 

 ephemera, 

 an insect.] 

 Fou n d e d 

 upon the 

 f ragm e n t 

 of an up- 

 per wing, 

 showing nervation and a heavy cross 

 vein near the base between two mid- 

 dle veins, from which new promi- 

 nent veins arise ; ancient May-flies, in 

 which the lower externo-median stem 

 seems to be formed on the same plan 

 as the upper stem. Type P. antiqua. 



antiqua, Scudder, 1867, Can. Nat. and 

 Geol., 2d ser., vol. 3, p. 202, and Acad. 

 Geol., p. 524, Devonian. 

 POLYERNCS, Scudder, 1884, Mem. Bost. Soc. 

 Nat. Hist., vol. 3, p. 343. [Ety. polys, 

 many ; ernes, a scion.] Body moder- 

 ately stout ; wings rather broad ; me- 

 diastinal vein extending nearly to the 

 tip of wing ; branches of scapular vein 

 inequidistant at origin, longitudinal, 

 closely crowded and ramose, yet hardly 

 more important than the externo"- 

 median vein. Type P. complanatus. 



complanatus, Scudder, 1884, Mem. Bost. 

 Soc. Nat. Hist., vol. 3, p. 343, Coal Meas. 



laminarum, Scudder, 1884, Mem. Bost. 

 Soc. Nat. Hist., vol. 3, p. 343, Coal Meas. 

 PBOMYLACRIS, Scudder, 1885, Proc. Acad. 

 Nat. Sci. Phil., p. 34. [Ety. pro, before ; 

 mylakris,a, kind of roach.] Body much 

 arched ; wing broad ; mediastinal and 

 scapular areas together not occupying 

 more than a third of the wing ; scapu- 

 lar area smaller than the mediastinal, 

 the vein running obliquely to the costal 

 margin. Type P. ovale. 



ovale, Scudder, 1885, Proc. Acad. Nat. 

 Sci. Phil., p. 34, Coal Meas. 



