WILLOW CATERPILLARS. 565 



17. Cerura occidentalis Liutner. 



(Larva, PI. xi, fig. 7. ) 



The caterpillars of this moth were found feeding on willows (Salix 

 nigra) by Prof. G. H. French, at Carbondale, 111., from September 9 to 

 October 5. The moths began to appear the following season from April 

 30 to June 3. 



Larva. — Length wbeu fully grown, L2o to the fork of the tail. Body slightly en- 

 larged iu front and somewhat compressed. In about the middle of the prothoracic 

 segment is a prominent projection on each side, the body sloping from these down to 

 the rather small head; there is but little sloping from the back to segment 9; 

 from this there is a rapid sloping to the anal segment, this ending in the two usual 

 caudal filaments; when withdrawn these are a little more than a quarter of an inch 

 long, but may be extended to three-quarters. Clear bright green, sides spotted with 

 clear purple brown, the spots ronnd the stigmata and at the base of the thoracic and 

 abdominal legs the largest. The back is marked with lilac, varying in shade, and 

 arranged as follows: From the two small contiguous tubercles on the back of joint 

 2 to the head is a somewhat diamond-shaped space, the broadest part at the sub- 

 dorsal tubercles on the prothoracic segment. From the tubercles on this segment to 

 those on the nest, the lilac is bordered by bright brownish purple with a white line; 

 outside of this, in the middle of this diamond, is a little green shading. From the 

 tubercles on the second joint from the head to the end of the body is another parti- 

 colored space, lighter than the anterior one. This gradually expands so as to in- 

 clude the stigmata on segment 7, then decreases in width to the anterior part of the 

 anal segment, expanding a little iu the middle of this, but contracting again at its 

 posterior part. The lilac of this is like the first, considerably suffused with green on 

 the back, and is bordered with brownish purple and white, though the colors are a 

 little lighter posteriorly. These two dorsal patches are not continuous, but are sep- 

 arated on the second segment by a distinct though small patch of green. The pos- 

 terior projections are mostly brownish purple, though with somewhat greenish an- 

 uulations, and when extended a ring of white near the extremity. Head dark lilac. 

 Previous to the last molt the tubercles on the prothoracic segment ("joint 1") were 

 covered with little spines. (French, Can. Eut., xiii, p. 144.) 



18. Cerura cinerea Walker. 



This species has been found feeding on the willow by Mr. Elliot, of 

 New York. 



Larva. — Pale apple green ; head brown ; second and third segment also with a 

 brown triangular patch not united to the brown dorsal patch. On the second seg- 

 ment are two raised rough processes, like horns, brown in color. Commencing on 

 the fourth and continuing to the last segment is a brown patch, a mere point on seg- 

 ment 4, spreading out diagonally on 6 and 7, narrowing on 8, a little wider on 9, 

 narrowing again on 10, and wider on 11 and 12. The anal segment is furnished with 

 long filaments alternately brown and green. -The lateral green spaces have a number 

 of rather small reddish spots, and on the dorsal brown patch are some small rough- 

 ened tubercles. Length, 1.30 inches. The younger stages are of a paler color in all 

 parts, without any perceptible diiference in the markings. (Edwards and Elliot, 

 Papilio, iii, p. 130.) 



Moth. — Forewings and thorax more ashy and dusky than in any of the other 

 species ; the broad mediau ashy band not being so distinct as in the other species, 

 since it is but little darker than on both sides of it ; the outer margin, also, instead 

 of being clear white or nearly so, is of the same dull ashy hue as the median band. 



