178 NEW YORK STATE MUSEUM 



brimful of struggling plant lice and particlc-s of whitened honeydew. It is 

 occasionally abundant enough to cause considerable damage, though as a 

 rule, the disfigurement of the tree and the shrubs below constitute the 

 principal nuisance. 



Life history. The life history of this species has been carefully worked 

 out by the late Professor Riley, who states that the over-wintering egg is a 

 minute, dull yellowish, ovoid t)bject about ' ;„ inch long, which is deposited 

 in cracks and crevices of the iiark during the summer. This remains 

 dormant till the leaf buds begin to swell, at which time the young plant 

 lice issue, crawl to the terminal lca\es and branches and settle on the first 

 tender leaflet they find. This is the first generation or stem mothers, and 

 they establish themselves on the under surface of the leaf and very soon 

 cause it to swell and curl, usualh' from one edge. The curl varies however, 

 depending somewhat on whether one or several stem mothers settle on the 

 same bud. The stem mother, at first pale yellowish red, with dark append- 

 ages, increases rapidly in size, dei)ending somt:what on the nourishment in 

 the leaf. In about 25 days young begin to appear at the rate of about one 

 to every si.x or seven hours, according to temperature. The colony 

 increases in numbers and earl\- in I urn- in this latitude, the affected leaves 

 may be literally overtlowing with plant lice and the honeydew they produce. 

 In favorable years the lice soon become so abundant that the leaves do not 

 protect tln-m, antl are covered with multitudes of old and young, some 

 wingless and others with organs of tlight. At this time the second genera- 

 tion of wingless mothers are surrounded liy smaller colonies, all of which in 

 turn ac(|uiri! wings. ()lhcr generations are jiroduced, as man\' as si.x 

 occurring in one season, the last depositing eggs in the cre\ices of the bark 

 as mentioned above. 



! )r Rllcy states that this species is very closely allied to the European 



S. u 1 m i Linn. 



Bibliography 



1880 Riley, C. V. & Monell, J. L". .S. (itd. (k-og. Sur. Bui. 5, p. 4-9 



