The present paper is the result of a study of the food plant relationships of Exema Lac. and Arthrochlamys Ihering (Chlamys Knoch) in Canada. The study has shown that the species have strong monophagous tendencies, and that a knowledge of food plants is the key to an understanding of those which have been confused under the names Chlamys gibbosa and C. plicata.

Resembling T. gillettei but somewhat larger. Two inner pairs of processes of aedeagus of about same length with innner pair not bent at middle and dorsal spine as long as shaft is wide. Length 4.5 mm.

Color: As in heavily marked T. gillettei V. D.

Egg: Ovate in shape, bluish green in colour, the surface divided by reticulations into small hexagonal areas. Laid singly on the needles of host tree.

First Instar: Head width 0.23 mm. Body 2.0 mm. in length and 0.23 mm. in width Brownish green body with light brown head.

Second Instar: Head width 0.5 mm. Body 4.6 mm. in length and 0.5 mm. in width. Body lined alternately with green and light green stripes. Spiracular line greenish white. Head brownish green.