Marshall—Ten Species of Arrenuri. 155 
in the form! of little hooks (X). Again, jnst forward of these 
is a pair of long triangular thickenings of the integument, the 
points toward the little projections just described (T 1 ). A lat¬ 
eral view shows that the appendage is moderately low, the high¬ 
est point a slight hump in the anterior half. There are five 
pairs of stiff hairs on the appendage. 
The form of the body corresponds closely with that of A. 
securiformis. The dorsal line runs over on the appendage and 
encloses an obovate area. The body is arched in the middle 
and has no large humps. There are numerous short stiff hairs. 
The fourth pair of epimera are unusually wide. The genital 
area forms outstanding rolls at the base of the appendage. 
The limbs show the characteristics common to Arrenurus 
males. The third, fourth and fifth segments of the last legs 
bear a great many long fine hairs, as well as many short,er 
bristles. The usual process is found on the fourth joint. The 
last segment of the palpi is forked, and the fourth is the longest. 
The color is pale dull green. The length of the body is 1.15 
mm; width, 0.725 mm; the height, 0.625 mm. 
Eight specimens of A. parallellatus were found in July and 
August, 1899, with A. securiformis at Wood’s Hole, Mass. 
Arrenurus comiger Koenike. 
Fig. 7, a—e, PI. XV. 
Arrenurus comiger Koenike, 1894 (b); S. 276, Eig. 1. 
Arrenurus comiger Piersig, 1901; S. 84. 
This form is easily recognized by the large cone-shaped hump 
on the anterior dorsal part of the appendage (Fig. 7, a and c, 
H 1 ). The horn-like projections on the anterior borders of 
the first two pairs of epimera are alsoi characteristic features. 
The petiole mentioned by Koenike was not found. The poste¬ 
rior of the three little humps near the end of the appendage 
(H 3 ) are pointed. The slighter form of the appendage, the 
slanting position of the genital areas, the more numerous hairs, 
are details in which the individuals examined do not conform 
exactly to Koenike’s text-figure. The body isi 1.02 mm. long, 
0.57 mm wide, and the appendage is 0.42 mm long. The 
color is light blue green. 
