February, '17] MANTER: BEAN WEEVIL 191 



was found to differ in several important points and to require some- 

 what different methods of control. These errors were copied and 

 recopied in many of the bulletins of our experiment stations for it 

 was not until about twenty-five years ago that some of the most 

 important phases of the life-history were correctly ascertained. 

 Doctor Lintner proved in 1891 that the bean weevil bred continuously 

 in dried beans, which was the most important observation made. 

 There are a few minor observations still to be corrected or yet to be 

 made. 



The Egg 



Doctor Chittenden gives the measurements of the egg as .o5-.7 mm. 

 long, being 2| times as long as wide. The average of several eggs 

 which I have measured proved to be .84 mm. long and .30 mm. wide 

 at the greatest diameter. The smooth white eggs are cylindrical ovate 

 and oftentimes slightly curved so as to resemble bananas in shape. 

 In storage the eggs are laid loosely in the container, at times being 

 fastened to the beans or receptacle and also may be deposited in the 

 exit holes in the beans. They may be laid singly or several in a cluster. 

 Lintner states that the "eggs are laid narrower end lower when at- 

 tached at an angle." I found of 261 eggs attached at an angle that 

 134, or more than one half, were placed with the larger end lower. 

 The eggs are so light that it would take nearly 40,000 to weigh a gram. 

 The lengths of the different life stages vary with the temperature and 

 the season. In my experiments the egg stage has varied from 7 to 17 

 days, the average for December at room temperature being 10 days. 

 Just before hatching the dark colored head of the larva shows through 

 the walls of the egg shell. 



The Larva 



The larva leaves through an irregular opening made in the larger 

 end of the egg. At first it has long legs with which it crawls about 

 seeking a suitable place at which to enter the bean. Lintner states in 

 his seventh report "it is highly probable that the aid given the larva 

 by the walls of the egg shell while still within it in concentrating, 

 guiding, and sustaining its muscular efforts, or that afforded by some 

 surface in contact as of an adjoining bean or the enclosing bag or jar, 

 is essential to its effecting an entrance." I had noticed that the larvae 

 always entered the bean where it was in contact with another bean or 

 other object. Beans were supported on the ends of pins and several 

 larvee placed on each. Many of them crawled down the pins while a 

 few entered the beans alongside of the pins. None entered elsewhere. 

 A small amount of vaseline was placed on the next lot around the 

 points so that the larvse could not leave by this route nor burrow into 



