11 



patches forming a broken subdorsal stripe on each side, the for- 

 ward end of which curves outward. The wings (Plate II., figs. 7 

 and 8) are slender, somewhat sword-shaped in form, unmarked, 

 and each wing is provided with a scale, which is connected by a 

 membrane to the posterior side of the base of the wing. The fore 

 wing has two longitudinal veins, and slight traces of one or two 

 cross veins may sometimes be seen. There is a row of small 

 spines upon the anterior margin and along each longitudinal vein. 

 The hind wing has a single median vein, upon which, near the 

 base, is a pair of rather slender spines directed backward toward 

 the body. Near the base of the costal margin is a row of four or 

 five short spines, hooked at their tips, which in flight engage a 

 membranous fold on the under side of the scale of the fore wing 

 (Plate II., fig. 9), and the surface of both wings is covered with 

 minute setae. Long fringes occur on both margins of the wings, 

 except on the basal fourth, that on the hind margin of the hind 

 wings being composed of a single row of spiral hairs, while that 

 on the hind margin of the fore wings consists of a double row of 

 spiral hairs. 



The legs (Plate III., figs. 23 and 24) are concolorous with the 

 body, and are sparsely set with fine hairs, in addition to which 

 there is a row of five or six stout spines upon the under side of 

 the hind tibiae. The tarsi (Plate III., figs. 16 and 17) are com- 

 posed of two segments, the division between them being very 

 oblique. The second segment is terminated by the remarkable 

 bladder-like structure which has suggested the name Physopoda 

 for this order. The bladder cannot always be seen, as it is re- 

 tracted when the foot is raised in walking and distended when the 

 foot is put down again. 



The abdomen consists of ten segments, of which the first seven 

 are dusky on the dorsum, except at the sides, and segment eight 

 has a dusky spot in the centre of the dorsum. The apex of the 

 abdomen is slightly dusky, and surrounded with black spines. 

 The hairs are scattering and fine except on the last two segments, 

 the next to the last segment bearing four short, stout spines near 

 the posterior edge of its dorsal surface. 



The wingless female (Plate I., fig. 3) is slightly longer than the 

 winged form, varying in length from 1.1 mm. to 1.65 mm., the 

 average being about 1.47 mm. The description of the winged 

 form applies to this, except that the general color of the body is 

 more yellowish, the dusky markings upon thorax and abdomen are 

 less distinct or wanting, and the dusky posterior border on the 

 head is darker and more prominent. The abdomen is slightly 

 more elongated, which may be due to its distension by eggs rather 



