POPLAR CATERPILLARS. 445 



escape which it carefully guards by means of a silken membrane re-enforced by frag- 

 ments of wood ; it then lines its burrow with silk and spins a firm cocoon about 

 itself. 



Kellicott calls attention to the very close mimicry of this moth after 

 certain wasps, seen in the form and color of the moth, its markings, 

 as well as its motions and attitudes. 



Larva. — The larvae, when taken, April 15, were of two distinct sizes, the larger 

 measuring from .9 to 1.1 inch in length, the smaller ,5 inch and less. The former 

 appeared to increase but slightly before pupation. Dull white with a darker line 

 along the back; head quite strongly bilobed, light brown, jaws and clypeus black ; 

 the first ring smooth, slightly clouded with brown, two irregular oblique marks from 

 the posterior border outwards to the front edge. Body somewhat attenuated toward 

 either end ; transverse wrinkles, especially on the thoracic rings, well marked ; in 

 the small ones there is a slight medio-dorsal indenture ; there are also lateral sub- 

 stigmatal wrinkles. Stigmata elliptical, brown, last pair large, placed subdorsally 

 and posteriorly. Above the anal feet, directed backwards, there are two black 

 chitinous teeth ; in the younger specimens they are more prominent and upturned. 

 The scanty brown hairs arise from slight papillae. 



Pupa. — Light brown. The clypeus is armed with a sharp wedge shaped process, 

 strengthened by ridges at its four angles and also by a median dorsal ridge. The 

 abdominal rings are furnished, as usual, with two transverse rows of teeth, except 

 the anal and pre-anal segments, which have but one row each. The terminal ring 

 is obliquely truncated, having several teeth. Length, .6 inch. (Kellicott.) 



Moth. — Blue-black ; fore-wings opaque ; hind wings transparent, with the border, 

 fringe, and transverse line near the middle black ; palpi at tip, collar, a spot on each 

 shoulder, and three bands on the abdomen yellow ; antennae short, black ; the four 

 posterior tibiae banded with orange ; tarsi yellow, tipped with black ; tail flat, with 

 two longitudinal yellow lines. Expands from I to 1^ inches. (Harris.) Kellicott 

 adds that the male is considerably smaller than the female, the antennae strongly 

 pectinated to the apical portion, which is enlarged and hairy. The abdomen has 

 four yellow bands and there are no "longitudinal yellow lines in the tail." Both 

 sexes have a conspicuous white spot bordering the eye in front ; four small yellow 

 spots on the upper part of the thorax ; two below the base of fore-wings, also a 

 yellow line at the outer edges of the collar; the outer edge of the coxae of the first 

 pair of legs, also those of the second and third pairs,are of the same color. The fore- 

 wings are more or less washed with red on the basal third. The second abdominal 

 band alone appears on the ventral side ; in front of it below is a yellow line. 



AFFECTING THE LEAVES. 



11. The stout poplar span worm. 



Bistort ursaria Walker. 



Order Lepidoi teea ; family Phal^nid^. 



In some seasons, during July, partially defoliating the Lombardy poplars in Mon- 

 treal, Canada, large drab or dingy purple span worms, at the end of July burying 

 themselves in the earth, the moths appearing during the last week in April and the 

 early part of May. 



According to Mr. G. J. Bowles (Can. Ent., viii, p. 7) this span worm 

 abounds year after year ou the Lombardy poplars in the city of Mon- 

 treal. " In some seasons the trees are partially defoliated by the larvae, 



