NORTH AMERICAN APTERYGOGENEA. I 77 



have observed in only one specimen. In the others they 

 are probably broken off. On the body, and especially 

 on the antennas and extremities, there also are extremely 

 fine long hairs, standing out at right angles. Skin scales 

 wanting. 



To judge from my materials, the color of the animal 

 seems to be rather variable. I am going to describe two 

 types. 



(i) Ground color dirty yellowish white. Along the 

 back a dark band runs, broken off at the joints, and in- 

 creasing in strength on the great abdominal segment. 

 On the thoracic segments the band has a rusty brown 

 color, passing on the abdomen into nearly black. The 

 antennae are dark yellowish, and have a thin covering of 

 dark violet color, increasing towards the ends of the 

 joints, where it forms real rings. The two outer joints 

 of the antennas often are dark violet. 



(2) Along the sides of the segments rather broad 

 black borders are running, which appear most distinctly 

 on the second and third thoracic segments and on the two 

 first abdominal segments; then they dissolve in extended 

 spots of the same color. Further inwards on the back, 

 near the middle line of the body, there run two rusty 

 brown lines of about the same width which are broken 

 off at the joints of the segments and finish on the second 

 abdominal segment. These lines also can be observed 

 on the great abdominal segment, but there they run a little 

 nearer to each other, are thin in the middle and increase 

 in breadth towards the ends. They do not reach quite to 

 the end of the segment. Two spots of the same color 

 are to be seen on the fifth abdominal segment. The ap- 

 pendicular parts are yellowish. The bases of the attennas 

 are encircled by black rings. Such rings also are met 

 with at the points of the three inner joints. 



Peoo. Cal Acad. Sci., 2d Ser., Vol. VI. ( 12 ) March 23, 1896. 



