1058 WALTER H. WELLHOUSE 



surmounted by a low cone with irregular ridges extending from base to 

 apex. From the apex of this cone there arises in some cases a short, blunt 

 prolongation, but often this is absent. The egg is without waxy covering 

 over the chorion, which is smooth, unsculptured, and of a shining dark- 

 brown color but somewhat lighter toward the base. The cap, or cone, 

 is often whitish. The egg, exclusive of the apical prolongation of the cap, 

 is 0.52 millimeter long, and 0.21 millimeter broad at its greatest width. 



The eggs are laid on the under surface of the leaf, in the axils formed by 

 the midrib and its lateral branches. Although the female has a well- 

 developed, sawlike, four-valved ovipositor, the eggs are not inserted into 

 the leaf tissue. They are placed among the hairs on the veins and are 

 in some cases glued together with an adhesive material. They are gen- 

 erally laid in small groups, some groups containing as many as eighteen 

 or twenty eggs; but occasionally they are laid singly. In counting 

 the number of eggs on one hundred infested leaves the writer found an 

 average of forty-nine eggs to a leaf. Occasionally a leaf had seventy- 

 five or eighty eggs on it. The egg-laying period extends over several 

 weeks, so that eggs, nymphs, and adults may be found at the same time 

 in July and August. 



Eggs laid on June 2 hatched on July 9 and 10, while the eggs of the 

 second brood, laid on July 29 and 30, hatched on August 15 and 16. This 

 indicates an incubation period of about thirty-seven days in the cooler 

 temperature of June, and eighteen days in July and August when the 

 average temperature was higher. 



The conical egg cap is pushed up by the nymph as it begins to emerge 

 from the egg still inclosed in the embryonic membranous sac. When 

 about halfway out of the eggshell the nymph splits the membranous 

 sac and slips it off over the head, leaving it with the egg cap on the outer 

 end hanging out from the empty eggshell. 



After emerging and drying, the nymphs begin to feed at once in colonies 

 near the eggshells. They molt five times, feeding from three to six days 

 between molts, the earlier stages requiring three or four days while the 

 later ones require five or six days. In molting, the cuticula breaks along 

 the median dorsal line from the front of the head to about the second 

 abdominal segment. The insect on emerging is limp, and is almost color- 

 less except for the eye facets which are bright red. The body color soon 

 darkens and the eyes a few .hours later become black. During the fifth 

 stage the nymph wanders about more freely over the leaf and in some cases 

 goes to adjoining leaves. Descriptions of the nymphal stages follow. 



First stage. Length 0.5 mm., greatest width 0.15 mm. General shape an elongate ellipse, 

 somewhat broader cephalad than caudad and more elongate than in the later stages. At 

 first almost colorless but saon becoming dark brown. Beak 4-segmented and extending 

 back to sixth abdominal segment. Antenna 3-segmented, the basal two segments being 

 shorter than the third segment; basal segment without spines or hairs, second segment with 



