38 ECONOMIC ENTOMOLOGY 



from "buds" in the larva. In the caterpillar, for example, from the 

 inner skin or hypodermis arise buds which develop into the wings 

 and legs of the butterfly. In a midge or fly the head with the eyes, 

 feelers, and jaws, are developed by an inpushing of the skin. The food- 

 canal, glands, and air-tubes of a moth or a bee arise from imaginal 

 buds. 



Imago or Adult Stage. — The pupa transforms into the imago or 

 adult insect. On the splitting of the pupal case the full-grown perfect 

 insect emerges. 



(c) Hypermetamorphosis. — With some insects more than two 

 intermediate stages may be noted in metamorphosis. In Meloe the 

 young larva {triunguUn) is thysanuriform; later it resembles a lamel- 

 licorn larva, being cyHndrical, fleshy, and less active (the scaraboeidoid 

 stage), then a pseudo-pupa (the coarctate stage), and later a legless 

 cruciform larva. In Epicauta also triungulate, carabidoid, scara- 

 boeidoid and coarctate or pseudo-pupa stages occur (Fig. 40). In 

 Platygaster, a proctotrypid, the following supplementary larval stages 

 are observed: (i) the cyclops, (2) the oval, and (3) the elliptical. 



Losses Due to Insects 



While everyone will acknowledge the fact that damage is done by 

 insects, the enormity of the losses is not generally recognized. How- 

 ever, fairly reliable data covering such losses for several decades 

 in the United States are available in State and Federal records. 



Every person admits large losses due to such pests as Potato Beetle, 

 Codling Moth, San Jose Scale, Tent-caterpillar, Cattle Horn Fly, 

 and Grasshoppers, but later pages will show many other injurious 

 forms that remain practically unobserved by the average person, on 

 account" of their small size, or their underground or boring habits. 

 The damage they do is often attributed to other causes, and frequently 

 reports are unreliable, unless corroborated by competent observers. 



The following estimate is based on statistics prepared by experts 

 and published in the Year Book, U. S. Department of Agriculture. 

 The loss on farm products, such as cereals, hay and forage, cotton, to- 

 bacco, truck crops, sugars, fruits, farm forests, miscellaneous crops 

 and animal products, valued at 8370 millions of dollars in 1909, is 

 greater than 10 per cent, for there is a loss of 972 millions, not includ- 



