APPENDIX F. MYK.IAPODS. 245 



The inferior surface of the last ring differs from the others in having 

 a much smaller shield, and in being provided on each side with a stout, 

 subcorneal spine, directed backwards. 



An immature specimen, one-third of the length of the one figured, 

 has the same number of segments or annuli, the same number of feet, 

 and the same general structure. 



One individual of this species was collected, on the 15th of June, at 

 Sweet-water creek ; others were found in July, between the south fork of 

 Red river and Otter creek. 



Plate XVIII, fig. 1, represents Scolopendra heros size of life, seen 

 from above. 



Fig. 2. The head from below. 



Fig. 3. Posterior extremity from below. 



Fig. 4. A medial segment to show the attachment of feet. 



Fig. 5. Disposition of ocelli on left side. 



2. Julus ornatus, Girard. 



Spec. char. — Ground-color bluish black ; segments narrowly mar- 

 gined posteriorly with reddish ; anterior margin of segments rather blue, 

 whilst the middle is rather black, thus giving the appearance of three 

 rings of color. The anterior portion, which is covered by the articula- 

 tion, is fulvous. Feet deep chestnut-brown. Antennae rufous at base, 

 blackish at tip. Stigmata not conspicuous ; marked by a series of small, 

 obsolete blackish spots. 



Remarks. — This species is allied to Julus marginatus of Say, but its 

 body is proportionally much stouter. The ocelli are disposed upon a 

 subtriangular space quite different in shape. The antennae themselves 

 are slenderer in proportions. The labrum (upper lip) is also less emar- 

 ginated than in Julus marginatus, and the marginal punctures much 

 less conspicuous. 



One specimen was collected on the 27th of June. 



3. Julus atratus, Girard. 



Spec. char. — Body, feet, and antennae, uniform deep blackish brown ; 

 antennae and feet occasionally reddish, as also the labrum and anterior 

 margin of first segment. Posterior third of each segment of a shining 

 black. Stigmata and lateral striae beneath quite conspicuous. 



