238 YELLOW-NECKED WORM THE PUPA. 



an inch in length, two black points surrounded by a pale yellow ring are 

 visible above upon each segment, and others upon the sides. From each of 

 these a white hair arises. These dots disappear as the worm becomes larger. 



The immature or tawny yellow larvae have black heads and feet, and a spot 

 on each of the prolegs, another on the tip and the two conical processes on the 

 apex are also black. They have four slender pale or sulphur yellow stripes 

 along each side of the body, and between the two lower of these stripes the 

 breathing pores form a row of black dots, one upon each segment. 



The mature or black worm grows to two inches or more in length, and has 

 the same pale yellow markings as the immature worm. The head is black and 

 without any spots. The second segment or neck is of a wax yellow color, and 

 the lower one of the four sulphur yellow stripes on each side of the body is 

 prolonged forward across this segment, with a black stripe contiguous to it on 

 its lower side, and on its upper side a wider black stripe reaches half way 

 across this segment. Above this the next sulphur yellow stripe is prolonged 

 upon the base of this segment and has a short black line upon its upper side. 

 Beneath, this worm has a sulphur yellow stripe along the middle and another 

 upon each side. These lateral stripes are interrupted by a wax yellow spot on 

 the middle of each segment, which spots are larger upon each of the feet-bear- 

 ing segments and are prolonged inwards, forming transverse bands across the 

 middle of these segments. The six anterior legs are black, the eight prolegs 

 are wax yellow with a black spot upon their outer sides. In place of the pair 

 of prolegs usually occurring at the end of the body this worm has two conical 

 processes, which are abruptly cut off at their tips, and project horizontally 

 backwards. They do not aid the worm in walking, being always elevated from 

 the surface over which it is moving. 



These worms are from six to eight weeks or more in growing 

 up to their full size. More than half of them are usually de- 

 stroyed, mostly, no doubt, by birds, so that of a brood of eighty 

 or a hundred worms which come from the eggs only from twenty 

 to forty are commonly remaining when they approach maturity. 

 It has been reported that the worms of each brood all reach ma- 

 turity at the same time and evacuate the tree in a single night. 

 But in many broods dwarfish individuals occur, which are 

 scarcely half the size of their fellows, and I have noticed worms 

 which were still engaged in feeding a week or longer after the 

 first ones of their brood had buried themselves. 



The pupa state of this insect, which lasts from September to 

 the following June does not appear to have been fully observed, and 

 I regret that I am not able at present to fully complete this impor- 

 tant link in its history. If Dr. Harris's observations have been 

 exact, there is some diversity in the habits of these -moths at this 

 time. He says they enter the ground to the depth of three or 

 four inches and within twenty-four hours cast their caterpillar 



