6 



BULLETIN 78, U. S. DEPARTMENT OP AGRICULTURE. 



Fig. :-i. — The tobacco Crambus: Full-grown larva, or "wireworm. 

 Much enlarged. (Original.) 



brown, flecked with darker brown. The cervical shield is distinct, shining, yel- 

 lowish brown, tinged with fuscous, and bears 12 hairs in two transverse equal rows. 

 The anal shield is pale fuscous. About the middle of abdominal segments 3, 4, 5, 

 and 6, and slightly above the spiracles, is a series of distinct, dark fuscous, chitinous 

 areas about the size and shape of spiracles, one to each segment. 



The arrangement of the tubercles is as follows: Beneath the anterior margin of the 

 cervical shield is a tubercle bearing two hairs. The mesothorax above bears eight 



setigerous tubercles on the 

 anterior margin, each, ex- 

 cept the lateral tubercle, 

 with two hairs. Posteriorly 

 it is provided with three bare 

 tubercles, of which the medi- 

 an is narrow and transverse. 

 The metathorax is armed, 

 as is the mesothorax. Each 

 abdominal segment above the spiracles bears two transverse rows of four tubercles 

 each. The anterior dorsal pair are subquadrate, with the posterior lateral angles 

 strongly rounded. The posterior dorsal pair are oblong, transverse, about half as 

 long as the anterior, with the posterior lateral angles strongly rounded. The anterior 

 lateral tubercles are supraspiracular, irregularly quadrate, with the lower margin 

 produced diagonally behind the spiracle, emarginate at the spiracle and before the 

 impressed area on segments 3, 4, 5, and 6. The 

 corresponding tubercle on segment 8 has the pro- 

 duced portion isolated and is placed anterior to the 

 spiracle. The posterior lateral tubercles are trans- 

 verse, elongate, and somewhat oblique. 



Abdominal segments 1 to 7 each bear a minute 

 spinule anterior to and nearly equidistant from the 

 spiracle and the supraspiracular hair. 



The legs are pale brown, the maxillary palpi 

 brown, and the mandibles brownish fuscous at 

 apices. 



The color of larvae collected from, differ- 

 ent food plants varies considerably, this 

 being merely an effect of the color, whether 

 light or dark, of the food in the alimentary 

 canal. Larvae collected from corn are considerably lighter than those 

 collected from tobacco. 



THE PUPA. 



The pupa (fig. 5) measures about 8 mm. in length and 2 mm. in greatest width. 

 The general color is dark brown, or pale yellowish brown when newly transformed, 

 with the appendages and segments marked with dark brown. The head is blunt, 

 with a median apical emargination . The tips of the wings are rounding on abdominal 

 segments; the margin of the inner wing is visible over segments 2, 3, and 4. The 

 spiracles are not prominent, the first three pairs being set on blunt tubercles. The 

 cremaster is transversely rounded oblong, with a lateral bristle near the apex. 



THE ADULT, OR MOTH. 



Expanse of wing, 13-25 mm. Head, palpi, and thorax dark fuscous, sprinkled with 

 gray scales. Fore wing dark fuscous, sprinkled with brown or yellowish, and fre- 

 quently with a few gray scales; median line dark brown, often edged with white, aris- 



Fig. 4. — The tobacco Crambus: Head 

 of larva. Greatly enlarged. (Origi- 

 nal.) 





