INSECTS AFFECTING PARK AND WOODLAND TREES 21 7 



dark gray scurfy patches, and if this be rul)bed with the oblique edge of a 

 knife or even witli the fingernail, an oily yellowish substance will be 

 crushed from the living insects under tlu; scales. This species breeds so 

 rapidly that it is not uncommon to find a large number on trees previously 

 comparatively free. Their presence under such circumstances is indicated 

 by a peculiar granular look and those familiar with the normal appearance 

 of the bark know that something is wrong. The plant tissues immediately 

 under the living scales are almost sure to have a! reddish discoloration, and 

 the fruit leaves and green twigs are usually marked by red blotches 

 encircling the scales [pi. 13, fig. 5]. 



The adult female is usually about 1/16 inch in diameter, nearly circular, 

 and with a central dark nipple, and one or more well defined yellow rings. 

 The young scales are nearl)^ black, have a central nipple, and one or two 

 grayish rings. The largest scales are just about the size of the head of an 

 ordinary pin, while the small ones are mere dots and resemble black specks 

 on the twig [pi. 13, fig. 6, 7 and 8]. The full grown female under one of the 

 larger scales is yellow, usually somewhat kidney-shaped, and without legs, 

 eyes or wings. She is, however, provided with a very long, slender pro- 

 boscis which is used to draw nourishment from the underlying plant tissues. 



Life history. The winter is passed by this insect in a partly grown 

 dormant condition. \'ital activities are resumed with the approach of 

 warm weather, and the first outward indications of life are seen in the 

 appearance of winged males and later of the crawling young, the latter 

 appearing in this latitude toward the last of June. The females produce 

 young for a period of about six weeks according to Dr Howard, averaging 

 about 400, or from 9 to 10 every 24 hours. The eggs develop within the 

 mother and the young are born alive. They may be seen as tiny yellow 

 specks escaping from under the maternal scale from which they wander in 

 search of a favorable place to establish themselves. This pilgrimage is 

 limited to a few hours, a little over 2ji,^ hours as determined by Professor 

 Lowe. The young soon establishes itself, inserts its slender proboscis 

 in the bark and begins to feed. The develojjment of the scale begins even 

 before the young has selected its feeding place, as very minute waxy fila- 



