. Annual report. Entomological Society of Ontario; Insect pests; Insects -- Ontario Periodicals. 1923 ENTOMOLOGICAL SOCIETY. 53 wide. Same as second instar except the thoracic colour markings more pro- nounced, and the wing pads extend beyond the first abdominal segment. Fourth Instar. Size mm. to mm. long, by .54 mm. to .72 mm. wide. Same as second instar except wing pads extend to posterior margin of second abdominal segment. Fifth Instar. Size mm. to mm. long, by .72 mm. to .81 mm. wide. Same as second instar except wing pads extend to the fourth abdominal segment. Emerg
. Annual report. Entomological Society of Ontario; Insect pests; Insects -- Ontario Periodicals. 1923 ENTOMOLOGICAL SOCIETY. 53 wide. Same as second instar except the thoracic colour markings more pro- nounced, and the wing pads extend beyond the first abdominal segment. Fourth Instar. Size mm. to mm. long, by .54 mm. to .72 mm. wide. Same as second instar except wing pads extend to posterior margin of second abdominal segment. Fifth Instar. Size mm. to mm. long, by .72 mm. to .81 mm. wide. Same as second instar except wing pads extend to the fourth abdominal segment. Emergence from Eggs. When hatching occurs the shell of the egg and the leaf epidermis are ruptured, and the soft, round, glossy nymphal head begins to appear slowly—oozing out as it were, like a globule of sap. The nymph gradually wriggles its way out; the appendages which are folded beneath the body slowly become free, and the nymph walks off with a wobbling Recently hatched leaf hopper nymphs on grape leaf (natural size). Habits. The nymph inserts its mouth parts into the leaf tissues and commences to imbibe the plant juices an hour or two after it emerges from the leaf; and it continues to feed throughout its entire life except when moulting or when disturbed. It feeds altogether on the underside of the leaf, preferably alongside a vein or in the junction of two veins; but under crowded conditions it will insert its proboscis anywhere on the lower leaf surface. Ordinarily the nymph will remain until reaching maturity on the leaf on which it was hatched out. It was commonly observed in the insectary that, even on the plants with fresh uninfested leaves, a small colony of nymphs would remain on one leaf until they reached the adult stage. On badly infested vines, however, the nymphs undoubtedly migrate to some extent. In making observa- tions on the hatching of the eggs, it was frequently observed that leaves from which all nymphs had been removed became infested overnight
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectinsectp, bookyear1872
