NORTH AMERICAN APTERYGOGENEA. I93 



gular. The cerci are distinctly cumulated with reddish 

 brown and white. The ground- color is yellow. The 

 scales are brown, alternately light and dark; the dark 

 ones arranged at the posterior margins of the tergits in 

 groups, symmetrically hanging down. The cuticula is 

 furnished with a network of chitinous bars. Within the 

 meshes the anchor-like cuticular figures are to be seen. 



The examination of this species has been of particular 

 interest to me, because the scales have remained quite un- 

 hurt. The head, rounded in front, is on the upper side 

 closely covered with dark brown scales. The antennce 

 resemble those of the preceding species. The points are 

 broken off, owing to which their length cannot be de- 

 cided. The maxillary palpi are 5 -jointed, with the ter- 

 minal joint thin and leg-formed. The labial palpi are 3- 

 jointed, with the terminal joint very much swollen. At 

 the basal joint a thin triangular chitinous scale is to be 

 distinguished. The shield - shaped thoracic tergits are 

 about equal in size and decorated with short light yellow 

 strias, regularly arranged. The first and third tergits are 

 at the posterior margin furnished with two, the second 

 with three incisions. On both sides of these the dark 

 scales are heaped downwards forming appendages, the 

 two lateral of which are rounded, the intermediate (one 

 or more) abruptly cut off. In at least eight abdominal 

 tergits such incisions also can be traced. Instead of 

 giving a detailed description of these and their number in 

 each tergit I refer to the drawing. The telson is short 

 and very distinctly annulated with reddish brown and 

 white. At the bases of the organs the rings are of small 

 extent and lie rather closely. Further out the alternating 

 colors extend over a great number of small segments 

 (4—5), and in the middle of the white rings a very fine 

 dark ring can be traced. The length of cerci cannot be de- 



Proo. Cal. Acad. Sci., 2d Ser., Vol. VI. ( 13 ) June 24, 1896. 



