Page:Wood 1865 - The Myriapoda of North America.djvu/80

Rh very readily to the preceding species, but it seems to me to fit this one rather more closely, and as the choice must be somewhat arbitrarily made in the absence of proof as to which he intended, I think the name should be allowed to rest here. Length, ½ inch.

The pilose anterior aspect of the head is quite broad and triangular, with the vertex furrows strongly pronounced. The first scutum is transversely oval, with three rows of elevated, obtuse, minute scales. On most of the other scuta there are two series of similar larger scales, with an obsolete series of very broad ones in front of them. The posterior row is generally composed of six, the next of four. The lateral lamina are large, and have their margins much more serrulate than in P. Canadensis. The last scutum is triangular and decurvate. The prominent knob-like portion of the male appendages is very hairy. The terminal spine is double, one portion being much more robust than the other, blunt and nearly straight. The longer piece is distally very slender and bent over the other.

Length ¾ of an inch.

It will be seen, on comparison of my description with the original one of Mr. Say, that it differs somewhat. The fact of Say's not mentioning the existence of the obsolete series of scales on the anterior surface of the scuta, has been the cause of M. Saussure's error. After carefully going over the whole ground, there is but little doubt in my mind that this is the species meant to be indicated by Say. If not, it is an undescribed species, and the real P. serratus has not yet come to light. It is an unfortunate fact that the earlier descriptions of Myriapoda are by no means exact, the authorities not appearing to have had any definite idea as to what constituted specific characters. If we interpret their records too closely, we may be led to false deductions.

Hab, Pennsylvania, &c.