8 BULLETIN 1336, U. S. DEPARTMENT OF AGEICULTURE 



THE PUPA (FIG, 9) 



Length of female 11 to 13 millimeters, average 12.17 millimeters; male 12 to 

 15 millimeters, average 13.71 millimeters. Width about 4.5 millimeters. Body 

 subcylindrical, with abdomen acute. Two pairs of minute seta? on front and other 

 minute seta? sparsely distributed over rest of body. Cremaster with two stout 

 spines bluntly curved at extremities, and on each side near their bases three 

 smaller setae curved and thickened at extremities. The spiracles are transverse 

 openings on tubercular prominences. In the female (fig. 10) the genital 

 opening is nearer the caudal margin of the seventh abdominal segment than in 

 the male (fig. 11). Surface of wing sheaths and prothoracic and mesothoracic 

 regions coarsely rugose. Dorsum of abdominal segments coarsely punctate, 

 ventrum sparsely punctate; caudal border of each abdominal segment smooth. 

 The pupa is pale yellowish-green when first formed but soon turns chestnut- 

 brown to fuscous, shiny, and sometimes almost black before emergence occurs. 



LIFE HISTORY AND HABITS 



ADULT STAGE 



EMERGENCE 



When the moth emerges, the pupal skin is broken along the 

 sutures of the head and thorax. One moth, after detaching itself 

 from the case, was observed to crawl rapidly away, coming to a 

 standstill with head upward on the stem of an alfalfa plant on which 

 it was allowed to crawl. Its wings, which were at first short, at- 

 tained full growth in the course of eight minutes. 



HABITS IN THE FIELD 



During the day the moths stay in hiding on the under side of 

 leaves or grass blades, sometimes in tree tops, and frequently under 

 the eaves and on the walls of barns and houses, where their dark 

 color enables them to escape notice. At dusk they become active 

 and in warm weather may be observed in the fields feeding on the 

 nectar of the blossoms of their host plants and flitting from plant to 

 plant. Their flight is zigzag and undulating, and on alighting they 

 quickly dart to the under side of the leaf or other object. If pur- 

 sued they frequently fly much higher than housetops and to a dis- 

 tance of some 50 to 100 yards away before alighting. 



In broad daylight they are not easily aroused; but at dusk they 

 are very timid, flying up at the slightest disturbance. When sud- 

 denly frightened, they often feign death and drop to the ground 

 with wings folded; but after an interval, if undisturbed, they crawl 

 rapidly along the ground and fly up when well out of danger. 



In order to find shelter for hibernation they collect on barns and 

 haystacks, where they are most often found during late fall, winter, 

 and early spring. They are active throughout the year, except 

 when the weather is extremely cold, and Chittenden {2) records one 

 flying at a temperature as low as 51° F. Both male and female 

 moths have been found to be attracted by lights. 



OVIPOSITION 



When ovipositing the moth partially raises her body and, while 

 slightly retracting and extending her ovipositor, curves the end of 

 her abdomen downward, its tip almost touching the surface on which 

 she rests. After several minutes in this attitude, a single egg is 

 quickly deposited. She then moves on to another restmg place, 



