December, '10] TiTUS: ALFALFA LEAF- weevil 469 



is very distinct, the remainder of the larva being green in color, some- 

 what lighter than that of the alfalfa on which it is feeding. The 

 length of the larva in this stage is 3.2 mm. to 4.8 mm. by 0.7 mm. to 

 1.1 mm. mde. 



With the third moult the larva becomes still darker green, the dorsal 

 line almost pure white, an indistinct white stripe on each side of the 

 body, and the white inverted "Y" on the face distinct. In this third 

 stage, the length varies from 5.5 mm. to 9.2 mm. by 1.25 to 2.25 mm. 

 wide (near the center of the body). 



Cocoon: When full grown, the larvae either crawl or drop to the 

 ground, usually the former, spinning their cocoons in the dead leaves 

 or other rubbish there present. When there is short dead alfalfa 

 present, such as that injured by frost, the cocoons may be found 

 in the dead leaves as high as six inches from the ground. 



The cocoon is globular, 5 mm. to 8 mm. in diameter, and is com- 

 posed of a rather coarse network of pure white threads. The larva, 

 in spinning this cocoon, at first curls into the same posture in which 

 it usually feeds, and begins to work a mass of threads on one side and 

 partly beneath it; later working its way into this small network and 

 then gradually carrying the network over from one side to the other, 

 and working in the cross threads connecting these portions. While 

 the larva is spinning the cocoon it often curls its anal end to the 

 mouth apparently to secure some secretion. Cocoons are usually 

 globular, especially those made in a curled leaf, but are often made to 

 fit the curl of the leaf. The larvae take from ten to twenty hours to 

 spin a cocoon, and usually do not moult into the pupa stage for from 

 thirty-six to seventy-two hours after the cocoon is formed*. 



Pupa: The newly formed pupa is pale green, the eyes somewhat 

 darkened, the posterior end of the femora, and the anterior end of the 

 tibiae rather dark. The abdomen has a pale dorsal line, and bears a 

 number of hairs at the extremity. There are a series of setae with 

 enlarged ends on each dorsal segment, but apparently few setae 

 on the ventral side. The length of the pupal stage averages about 

 eight days. 



Moulting: The larvae in all stages seem to have the same general 

 process of moulting. This casting off of the skin is rather a slow 

 process. The first evidence is the slight shortening of the larva, soon 

 followed by the splitting of the head plate, beginning at the center 

 of the inverted "Y." This split increases in three directions along 

 the inverted "Y, " the parts rolling back and allowing the head to be 

 protruded, the split then spreads a short distance down the back, 

 rarely more than two segments, the larva working its way out through 

 this opening. The cast skin soon dries and shrivels up, so that it is 



