INSECT PESTS OF OHIO SHADEAND JROItfcji t$E$$ 265 



THE IMPERIAL MOTH 

 (Basttoma imperialis Drury) 



The imperial moth is a little more abundant than the preceding 

 species. It, too, is given consideration in the present bulletin not 

 so much on account of its economic importance but because of the 

 interest attracted by the striking appearance of the larva. 



Description. The full-grown larva has been described by Dr. 

 T. W. Harris as follows : "They are from 3 to 4 inches in length and 

 more than one-half of an inch in diameter, and, for the most part 

 of a green color, slightly tinged with red on the back ; but many of 

 them become more or less tanned or swarthy and are sometimes 

 found entirely brown. There are a few very short hairs thinly 

 scattered over the body ; the head and legs are pale orange colored ; 

 the oval spiracles, or breathing holes, on the sides, are large and 

 white, encircled with green; on each of the rings, except the first 

 there are six thorny knobs or hard and pointed warts of a yellow 

 color, covered with short black prickles ; the two uppermost of these 

 warts on the top of the second and third rings are a quarter of an 

 inch or more in length, curved backward like horns, and are of a 

 deeper yellow color than the rest; the three triangular pieces on 

 the posterior extremity of the body are brown, with yellow margins 

 and are covered with raised orange-colored dots." 



In the writer's observations, the brown and green forms were 

 almost equally abundant, and during the course of the study an 

 attempt was made to correlate the color forms with certain food 

 plants. After 2 years' observation, however, his data did not indi- 

 cate that the kind of food had any bearing upon the coloration of 

 the larva. An idea of the general appearance of the larva may be 

 had by referring to Plate XLI, Fig. 2. 



The pupa is dark brown, about 1% inches long and is found 

 beneath the surface of the soil. 



The adult is a very beautiful moth. The fore wings are yellow 

 with pale lilac lines and areas. The hind wings are yellow also, with 

 a somewhat less amount of the lilac markings. 



The eggs are nearly one-eighth of an inch long, white and some- 

 what flattened with a distinct equatorical ridge. 



Life history and habits. The winter is passed as a pupa, the 

 moths emerging in June and depositing eggs. The caterpillars 

 hatch and mature in late September or early October. They then 

 pass to the ground and construct their over-wintering cells. So far 

 as known, never more than one brood develops in Ohio per season. 



