P. corrugatus. Blackish chestnut, with yellowish lateral laminæ, and the scuta posteriorly margined with yellow.
P. bifidus. Reddish chestnut, with yellowish lateral laminæ and the scuta both anteriorly and posteriorly margined with yellow.
P. trimaculatus. Deep reddish brown, with three bright orange spots on each scutum.
P. crassicutis. Very large. Scuta irregularly subrudely punctate.
Subgenus Leptodesmus.
Dorsum strongly convex. Lateral laminæ small.
P. placidus. Olive brown. Scuta banded with black. Lateral laminæ light brown.
P. floridus. Blackish chestnut; scuta margined posteriorly with reddish orange. Lateral laminæ orange.
P. Haydenianus. Olive chestnut. Lateral laminæ yellowish.
Subgenus Strongylosoma.
Body cylindrical. Lateral laminæ very small.
P. eruca.
Fam. IULIDÆ.
Posterior subsegments, with their sterna atrophied. Segments numerous, without lateral laminæ.
Genus Iulus.
The second scutum not produced anteriorly at the sides so as to abut against the head.
a. Last scutum mucronate.
* Mucro small.
I. impressus. Reddish chestnut. Segments 52. Scuta scarcely at all pilose.
I. pilodscuta. Brownish chestnut. Segments 58. Scuta very pilose.
I. Oregonensis. Bright chestnut. Segments 45. Scuta scarcely at all pilose.
** Mucro large.
† Mucro uncinate.
I. Canadensis. Brightish chestnut, with a black dorsal stripe and series of black dots on each side. Segments 53. Mucro very large.
I. immaculatus. Dark reddish brown, immaculate. Segments 51. Mucro moderate.
†† Mucro straight, or nearly so.
I. Pennsylvanicus. Segments 63. Scuta on the upper surface distantly and obsoletely canaliculate.
