132 ENTOMOLOGICAL NEWS. [May, '05 



the territory inhabited by the insect is especially suitable for 

 the development of the food plant, which is a little Crucifer 

 thai grows in the sandy soil on the rocks. 



The males are the first to appear, and single specimens may 

 be seen in the latter part of April. They do not become 

 abundant until the 6th or yth of May, and then an occasional 

 female (about i 9 to every 10 S 's) may be seen among them. 

 Between the loth and iSth of May the females are almost as 

 common in one instance they were more common than the 

 males ; but shortly after the latter date, all disappear suddenly. 

 The first appearance is liable to be retarded by a cold tempera- 

 ture and consequently the dates may be shifted backward a 

 little. 



Females were observed depositing eggs May nth, and the 

 first larvae hatched on the day following. The egg is cylindri- 

 cal, broadest at the middle, slightly narrow at the base, and 

 tapering rather acutely at the apex. It is orange in color, and 

 under the power of a ^-inch objective shows about fifteen ver- 

 tical ribs, with numerous faint cross ridges between. 



The eggs are laid singly on the stem of the food plant Arabis 

 lyrata, immediately below the terminal bud of the plant and 

 large plants may have as many as four eggs. This is slightly 

 different from a note published by Mr. Hornig (ENTOMOLOGI- 

 CAL NEWS, Vol. XIV, p. 252), who says : " As a rule there 

 is only one egg on a plant, although two have been collected 

 on large healthy specimens." The food plant in this instance 

 was Sisymbrium thaliana. 



From the lot of eggs collected on May nth, nothing was bred, 

 for as soon as they hatched the young larvae fell prey to a 

 small black spider which spins its web on the plant. There 

 were several such in the cage which were not noticed until the 

 entire lot of larvae had been destroyed. 



On May iSth I saw an isolated female in the valley, below 

 Garret Mountain, which had evidently wandered from its 

 breeding grounds ; it was flitting gently about, stopping at 

 short intervals on a white blossom which was afterwards 

 determined as spring cress (Cardamine rhomboidea). A close 

 examination of the blossoms revealed on each an egg tucked 

 beneath, close to the calyx. 



