April, '11] HINDS & turner: rice weevil 231 



"pear-shaped," with the larger end outward as it rests in the grain 

 (PI. 1 , fig. 2). The covering membranes are thin and of an opaque 

 white color. The average length of eggs is about 0.665 mm. by about 

 0.295 mm. thickness at the larger part. The young larva can be seen 

 through the egg covering shorth^ before it is ready to hatch. Hatching 

 occurs in an average of three days from deposition of the egg with 

 a mean temperature of between 60° and 65° F. There appears to be 

 a considerable mortality during the egg stage as not nearly as many 

 larvse develop in corn as there are eggs deposited, but the exact pro- 

 portions have not been determined. It appears to be fully 50 per 

 cent, however. 



The Larva. — This stage has been figured by a few writers. Photo- 

 graphs are here shown of the young larva as it hatches from the egg 

 and also of the fully grown larva (PI. 7, figs. 3, 5). The grub is of a 

 creamy white color except the head which is brownish shading to 

 nearly black at the tips of the mouth-parts. It is very thick bodied, 

 with the ventral line approximately straight while the dorsum is almost 

 semi-circular. There are three larval stages as shown distinctly by 

 the measurements of heads. In the first stage the head averages 

 approximately 0.22 mm. in breadth at its widest part; in the second 

 stage, 0.33 mm. and in the third stage 0.64 mm. The first larval 

 stage requires about three days, the second four days and the third 

 nine days on the average, with mean temperatures of between 60° and 

 65°F. There is then a cUstinct prepupal stage in which the forming 

 pupa is plainly visible through the unshed larval skin lasting for 

 usually one day. The entire larval stage, therefore, requires between 

 sixteen and seventeen days on the average, with a common range of 

 between fifteen and nineteen days under usual temperature condi- 

 tions. The pupal cell is always formed within the kernel and may 

 be either in the heart of the kernel or near its exterior. 



The Pupa. — This instar is somewhat longer and more slender than 

 was the grub before it (PI. 7, fig. 6). There seems to be considerable 

 variation in length of this stage at the same period, with the average 

 at about six days and the range between three and nine days. Con- 

 siderable brown coloration appears before the pupal skin is shed. After 

 the insect has become adult it still remains within the kernel for 

 several days to harden and fully mature before it makes any attempt 

 to escape. 



Naturally, with all of the immature instars, the duration of the 

 stage is very largely determined by prevailing temperature conditions. 

 The records that have been given relate to observations ranging 

 from about the middle of August to the early part of November in the 

 latitude of Auburn, Ala. The breeding of weevils continues more or less 



