178 POLIASPIS CYCADTS. 



Diaspinds (PI. XVII, fig. 3) ; the three anterior groups 

 each consists of from 2 4 glands ; are arranged in the 

 form of a semicircle; the sub-anterior group also 

 consists of 2 4; the anterior laterals of from 10 1 :> ; 

 and the posterior laterals from 21 25. My series is 

 much too small to give a correct average of the number 

 of glands, but I gather from Comstock's description 

 that they are not subject to great variation. Dorsal 

 tubular spinnerets, short and cylindrical, are in eight 

 distinct series, forming two incomplete, ellipsoidal 

 arches, the first embracing the five superior groups of 

 circumgenital glands ; the remaining four groups 

 completing the second arch.' The preceding segment 

 has also a series of 7 8 tubular spinnerets placed 

 near the articulation, and there are 7 8 others of 

 similar character, but smaller, arranged along the 

 margin. Anus opposite the sub-anterior group of 

 glands. Vaginal opening in the centre of the space 

 between superior groups. The median lobes (PI. 

 XVIII, fig. 6) are large, slightly divergent, usually 

 finely and widely serrate or entire; the second pair of 

 lobes are small, and have the margin widely rounded ; 

 third pair usually obsolete or very minute. Comstock 

 (I. c.) says the second lobes are divided, but I do not 

 find this character in my examples. The plates air 

 simple and spine-like ; there are three between the 

 median lobes and the first series of tubular spinnerets, 

 and one between the latter and the next series, which 

 are much the largest ; the rest of the margin has about 

 seven others, much shorter, and Avith suddenly dilated 

 bases. Spines short ; there is one on each side of the 

 median and second lobes, and one near the third and 

 fourth plates. 



Puparium of the male (PI. XV, fig. 4) elongate, is 

 either straight or curved, and non-carinated, and com- 

 posed of a white felted material as in Chionaspis. 

 Larval exuviae pale yellow. 



Long. 1 1*25 mm. 



Perfect male unknown. 



