190 THE MONTHLY BULLETIN. 



Copulaiion and Oviposition. — Three days after the adults were seen 

 mating, egg laying began and continued three days. When about 

 to deposit an egg the female lowers the abdomen and extrudes the 

 ovipositor which comes in contact with the plant. She remains in 

 this position for several minutes, during which the egg stalk passes 

 into position and is firmly cemented to the plant. When the cement 

 has set the female quickly withdraws her ovipositor, leaving the egg 

 and stalk in an upright position. After the egg is placed the Psylla 

 walks away and usually begins feeding. 



THE EGG. 



The egg is minute, smooth and shiny, aliout 1/80-incli in length and 

 1/200-inch in width, obtusely rounded at one end, somewhat tapering 

 at the other. The dorsal surface is slightly concave. The egg is sup- 

 ported in an upright position by a short pedicle. When first laid it 

 is of a light yellow color, but darkens posteriorly as the embryo d(,'velops. 

 In advanced stages the two red eyes of the immature insect are visible 

 through the transparent eggshell. Eggs are deposited singly on all 

 surfaces of the leaves and young growth. The number deposited by 

 three females under observation averaged thirty-six. Egg laying began 

 three days after mating and continued three days. The incubation 

 period in a hothouse was fifteen days. 



The Hatch hig Process — After the shell is split the nymph propels 

 itself forward by body movements until the legs are free, after which 

 it rests for several minutes. When work is resumed the nymph frees 

 itself from the shell, but remains head downward clasping the empty 

 shell and stalk for about fifteen minutes, after which it descends to 

 the plant, clasping the pedicle for support. Usually the newly hatched 

 nymph immediately crawls to the under side of a leaf, inserts its beak 

 into the tissues and begins feeding. 



THE NYMPHS, 



When first hatched a nymph is minute, only slightly larger than the 

 ego". The body is flattened and oval in shape, semi-transparent, the 

 abdomen being partly yellowish. The eyes are red and conspicuous. 

 The margin of the body is fringed with numerous wax glands which 

 give rise to glandular hairs. These hairs are cast with each moult. 

 The glands about the anus cover the liquid excrement with a layer of 

 wax as it passes out, so that it is slowly and gradually discharged in 

 tiny white pellets which, if undisturbed, gather in large quantities, 

 ffiving the plant the appearance of having been sprinkled with sugar. 

 The nymphs are usually content to remain quietly feeding, only occa- 

 sionally moving to more favorable locations. 



Later the color markings are variable. Usually brownish, orange 

 or greenish markings appear on the body a7id head a short time after 

 the first moult, and wing pads appear as lateral buds. In the advanced 

 nymph the hinder segments of the abdomen appear to be fused together, 

 the traces of segmentation being obliterated. The great wing pads are 

 the most conspicuous featnre. Tlic nymph i)asses througli five instars. 



