100 Indian Economic Entomology, [Vol, I. 



"That the juices of the opium poppy in protecting the plant against the 

 attacks of insects renders the opium poppy very different in this respect from 

 otVier poisonous plants, the poisonous principles of which, however deadly, do not con- 

 fer on the plant immunity from the attacks of some insects. Moreover, certain poison- 

 ous plants are eaten without any ill effects by certain insects, which also derive a share 

 of their food from other and non-poisonous plants." 



Besides occurring- in India, Helioihis armigera is found in Ceylon, 



The pest in other parts Java, Australia, New Zealand, Europe, North and 



of the world. South America> and the W est Indies ;— it is, in 



fact, cosmopolitan. In 1885 Dr. Riley published an account of the 

 insect, in the 4th report of the United States Entomological Commission, 

 and the following is an abstract of his paper. 



The Noctues moth Heliothis armigera, which is commonly known in 

 America as the Boll Worm, may be considered to be one of the foremost 

 of injurious insects in America. In many parts of the Southern States 

 it is the chief cotton pest, while, taking 1 one year with another, there can 

 be little doubt but that maize suffers more from it than from any other 

 one pest, not excepting the Clinch Bug. With tomatoes, peas, and beans, 

 though the injury is not great generally, yet occasionally much damage 

 is done locally. There are at least three generations in the year that attack 

 maize ; the later generations attacking cotton. It is to the pest as found 

 attacking the cotton plant that Dr. Riley's paper chiefly refers. The 

 habits of the insect, however, are pretty certain to be identical, at least 

 throughout North America, upon whatever food-plant it may be found. 



A single female is able to lay as many as five hundred eggs, which 

 are nearly white in color, and may easily be seen against the green back, 

 ground, deposited all over a cotton plant. The favorite time for oviposi- 

 tion is at dusk, when the moths may be seen flying in great numbers 

 about the cotton-fields. The eggs generally hatch in about four days 

 after they are laid. The time, however, varies with the temperature, 

 warmth accelerating and cold retarding development. At first the 

 young larva feeds on a leaf close to where it emerged from the egg, but 

 it soon begins to crawl about the plant, often lowering itself by a silken 

 thread, and feeding upon the leaves all over the plant. Occasionally it 

 completes its growth and becomes full fed upon the leaves alone. Usually* 

 however, long before it is full fed it bores into some bud or boll. Dr. 

 Riley writes— 



" As the worms grow they attach larger bolls, the young larvse having mainly 

 confined themselves to the buds and newly-formed boil, 'the worms may therefore 

 be said to progress downwards, the younger individuals being found maiuly upon the 

 top crop, while the older larva? bore into the older bolls of the middle crop, the bottom 

 crop being seldom seriously damaged by Heliothis. The half-grown worm, finding a 

 boll of suitable age, begins at once to gnaw through the smooth covering, soon forming 

 an opening as large as the diameter of its body, and through this opening it gradu- 

 ally works its way into the interior of the boll. Frequently the spot first tried proves 

 too hard or otherwise distasteful, and the worm leaves it either for another boll or for 

 another spot on the same boll. Infested bolls can usually be distinguished by the 



