I08 THE APPLE LEAF HOPPER 



An idea of its present alnindance in this section may be gained 

 from the fact that a farmer of our acquaintance counted in a small 

 piece of woodland several hundred of these "webs" in the morning 

 sunlight after a night of fog had left the nests conspicuous. 



They work mostly at night, for they were generally observed to 

 be quiescent during the day, while a light flashed upon them at night 

 revealed them as being extremely active within the web, rapidly de- 

 vouring the leaves they had enclosed, and extending their web over 

 other leaves. 



ITS LIFE HISTORY. 



The moth is characteristically white in color, at least in Minne- 

 sota, but its wings are frecjuently marked with spots, and the varia- 

 tions are so marked that the insect has in the past received two or 

 three different specific names on this account. Lugger (Fourth An- 

 nual Report, Minnesota Entomologist) states that breeding them in 

 confinement has proven these markings to denote simply variations 

 of the same species. 



The female lays its eggs at night, in a cluster, on a leaf of its 

 food plant, one female being capable of depositing four hundred or 

 more eggs. The egg (about 1-50 inch in diameter) i.s light yellow, 

 round, and its surface ornamented by indentations easily seen with 

 a lens. The eggs hatch in about ten days, sooner if the weather is 

 warm, and the young caterpillar at once begins its work of destruction. 

 In states where there are two broods, it is calculated that the offspring 

 from a single female could reach, under favorable conditions, the 

 astonishing number of 125,000 caterpillars in a season. Even in Min- 

 nesota, where, it is believed, we have only one brood, the progeny 

 of one female may reach the 500 mark, and it is this fecundity, and 

 the very generally prevalent habit on the part of our citizens of over- 

 looking its work, that the entomologist wishes to emphasize as an 

 alarming feature in connection with our trees. 



The newly hatched caterpillars are yellowish and hairy, with a 

 black head; as they grow older they may change to greenish, or be- 

 come paler or darker, showing a marked variation in this respect. 



The web, which is made larger as the caterpillars grow older, 

 spreads over the branch, or to other branches, and finallv filled wdth 

 the remnants of the eaten leaves, with the moulted skins of the cater- 

 pillars, and with their excrement, becomes disgustingly prominent. 



In a month or six weeks these caterpillars are full grown, a little 

 over an inch long. They spin their cocoons in sheltered places, in 

 the litter on the ground beneath the tree, in clefts and crevices in 



