780 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



106. The red-head inch-worm. 



Semiothisa bisignata (Walker). 



(Larva, Plate vi, fig. 3.) 



This is one of the most common of the inch or span worms which live 

 at the expense of our coniferous trees. It occurs abundantly on the 

 white pine in the neighborhood of Providence as late as October, and 

 in Maine, at Brunswick, occurs in July, August, and September. Its 

 green body is of the hue of the leaves among which it lives, while the 

 reddish sides of the head, and the reddish thoracic legs are in harmony 

 with the tints of the reddish sheaths of the pine needles ; the white 

 lines are like the white lines on the needles ; hence it would be difficult 

 we imagine for an insectivorous bird to detect such a caterpillar. It is 

 to be found in Maine not only on the white and pitch pine, but on the 

 spruce and fir. It transforms into a chrysalis in August, and through 

 September as late as the 20th, and appears the following June, not 

 spinning a cocoon, but entering the earth to pupate. I have found it 

 difficult to keep the pupse over winter, and was fortunate after several 

 unsuccessful attempts at hibernating the pupa, to have one moth issue, 

 November 15, and to find that it belonged to a well-known species, 

 which flies commonly in j)ine woods throughout New England in June. 



In the neighborhood of Providence I have noticed that the caterpillar 

 is often without the reddish patches on the sides of the head. 



Larva. — The body is of the width and length of a fir leaf, being rather thick and uni- 

 formly so. Head green in the middle, bright reddish on the sides, mottled with red- 

 brown, and with two converging, narrow oval, pale red spots in front just below the 

 vertex ; clypeus tinged with red. Body pale green ; a broad dorsal whitish green 

 band of the same color as the under side of a fir leaf, and containing a median darker 

 dorsal stripe. The band is whitish on the edges, next below which are two very 

 narrow dark-brown hair lines. A whitish line below the stigmata, and still farther 

 below a narrow whitish line, and two parallel dark subventral lines. The thoracic 

 legs reddish ; the abdominal legs green. Length 18-20™™. 



Pupa. — Body of the usual shape, and mahogany-brown color, and of the usual pro- 

 portions, with the surface rather coarsely i)itted. The cremaster is a rather broad 

 stout spine, ending in a rather long slender cylindrical spine ; there are no curved 

 spinules on the sides, as in the species which spin a cocoon. Length 11 to 12™™. 



The moth. — Antennae of male flattened, serrate, ciliated. Forewings as falcate as 

 in S. prcBatomata ; hind wings very much angulated, more so than in S. prceatomata, 

 the angle being very marked. Head, antennae, and palpi bright reddish-ocherous. 

 Body and wings whitish-ocherous, gray, densely speckled with brown, being much 

 paler than usual. Forewings crossed by three brown lines, arising from moderately 

 sized costal spots. The inner line much carved, somewhat angular below the costa, 

 but not enlarged on the costa. Second line arising from a rather large light-brown 

 costal spot ; it is not curved and is rather diffuse. Outer line tremulous, curved out- 

 ward between the costa and median vein, darker on costa. A reddish-brown, oblong, 

 broad costo-apical spot nearly touches the line ; this spot is continued across the wing 

 by a faint reddish shade, especially marked between the first and second median 

 venules. Below this spot, in the middle of the wing, the marginal brown line, else- 

 where not interrupted, is continuous and well marked in the apical sinus. No discal 



