268 



A A' ECONOMIC ENTOMOLOGY. 



ally its natural enemies keep it in check, but sometimes it seems 

 to outrun them, and then for a series of years in succession it 

 becomes increasingly abundant until, as suddenly as it increased, 

 it disappears so nearly that nothing will be seen of it for a few 

 years. If the insect is taken in hand as soon as noticed, cutting 

 down and destroying the newly formed nests with all the cater- 

 pillars they contain will pro\e the most satisfactory remedy, or 

 the foliage just surrounding them may be sprayed with an arsen- 

 ical mixture. 



There are other species in this series, like those belonging to 

 the genus Halisidota, which sometimes infest shade trees, but 

 rarely in numbers sufficient to be troublesome. The caterpillars 

 may be distinguished by having slender pencils of hair, and some- 

 times a series of dorsal tufts. The moths are brownish yellow, 

 with rows of semi-transparent and irregular, light-brown spots 

 arranged almost in bands. Economically none others of the 

 Ardians are troublesome, though we have many species that are 

 common enough when sought for. 



In the family Lvniantiiidcc we have what are known as the 

 "vaporer, " or "tussock moths." Of these the Notolopluis 

 {Orgyia) /ciicostigDia, or "white-spotted tussock-moth," is 

 the most common. It feeds on a great variety of trees in the 



lar\'al stage, and is 

 seriously troublesome 

 in cities and towns. 

 The caterpillars are 

 rather pretty creat- 

 ures, with bright red 

 heads resembling 

 sealing-wax in ap- 

 pearance, and yel- 

 low bodies bearing a 

 series of dense, abruptly cut off brushes on the middle of the 

 back, and two pencils of black hair anteriorly. They are rather 

 more than an inch in length, when full grown crawl down the 

 trees, and, either on the trunk or somewhere in the vicinity, under 

 any projecting point on fence-rail or the like, make their dirty- 

 whitish cocoon of mixed silk and hair. In due time the adults 

 emerge, the male bearing fully developed wings, while the 



Fig. 290. 



f-T*"^. 



Caterpillar of Notolophus leucnsti^nia. 



