THE CANADIAN ENTOMOLOGIST 197 



first taken by Mr. L. C. Bragg upon knot-grass or door-weed, 

 Polygonum sp., at Ft. Collins, Colo., in July, 1907, and we have 

 had it under observation each year since and throughout the 

 growing season. 



Apparently, the different species of Polygonum are the sole 

 food plants of this species. It imitates the colour of the under- 

 side of the leaves and the stems of the plants upon which it feeds 

 so perfectly that it is seen with some difficulty, and it is sporadic 

 in its habits. The lice also have the habit of working beneath 

 the bracts at the bases of the leaves where they are out of sight. 

 The different stages may be described as follows: 



Apterous Viviparous Female. — Colour green, with tips of the 

 antenna^, the tarsi, distal ends of tibise, and extreme tip of cornicles, 

 dusky to blackish; form of body long and tapering posteriorly to 

 the point of the pre-caudal shield; body, legs and antennae very 

 free from hairs; antennae upon slight tubercles, 5-jointed; joints 

 4 and 5 and spur sub-equal; joint 3 as long as 4 and 5 together, 

 total length about .40; legs short and stout; cornicles a little more 

 than one-half as long as the hind tarsi, placed at extreme lateral 

 margins of abdomen, weak, recumbent upon the abdomen, clavate, 

 rounded and without flange at the distal end, the opening being 

 on the inner side near the end; cauda long, slender and entirely 

 hidden from above by a triangular shield-like projection of the 

 pre-caudal tergite which extends beyond the end of the cauda; 

 lateral margins of prothorax and abdomen without spines. See 

 plate XI, figures 10 to 14. 



Winged Viviparous Female. — General colour, pale yellowish 

 or greenish yellow, eyes blackish, head, mesothorax above and 

 below^ metathorax above, antennae and tarsi dusky brown; wing 

 veins heavy and dusky brown to blackish; length 1.40; antenna 

 .40 to .50; wing 1.80; head rather broad and flat, the antenna 

 being widely separated and not upon distinct tubercles, 5-jointed; 

 medium ocellus prominent on the vertex; joints of the antenna: 

 III, .18; IV, .08, V, .07; spur, .08. Joint 3 has about 6 to 8 sen- 

 soria; joint IV, 1 near the distal end; joint VI, 1 large and 4 or 5 

 small ones; antennal segments free from hairs; prothorax rather 

 large and without lateral tubercles; cornicles, concolorous with the 

 abdomen, situated on extreme margins, weak and lying against 



