15 
Table 5. — Comparative larval abundance and development by stages of 
Hypera b runneipennis in alfalfa and sourclover. 
Yuma. Ariz., 1940 
Field 
"Date 
Grove" 
alfalfa 
"Pecan 
Grove" 
sour 
clover 
area 
Date 
Instar 
sampled 
1st 
2nd 
3rd 
Jan. 
3 
__ 
— 
__ 
Jan. 
8 
— 
— 
~ 
Jan. 
15 
0.75 


Jan. 
22 
16.00 
2.00 

Jan. 
29 
18.50 
1.50 

Feb. 
5 
33.13 
5.13 

Feb. 
14 
25.63 
6.25 
0.75 
Feb. 
20 
19.13 
4.25 
0.25 
Mar. 
5 
3.88 
4.00 
0.25 
Mar. 
19 
9.25 
0.88 
0.50 
Mar 
25 
2.25 
0.13 
0.25 
Apr. 
2 
1.75 

0.13 
Apr. 
8 
0.25 
• 0.25 

Mar. 
13 
9.86 
5.43 
4.43 
Mar. 
20 
16.00 
3.86 
2.71 
Mar. 
27 
9.14 
6.86 
4.86 
Apr 
2 
7.00 
3.29 
4.57 
Apr. 
10 1/ 
0.13 
0.38 
0.63 
Apr. 
16 



Apr. 
22 



Apr. 
29 



May 
6 



Nu mber of larv ae p er squ are foot 
4th Total 

0.75 

18.00 

20.00 

38.25 

32.63 

23.63 
0.13 
8.25 
0.38 
11.00 
0.13 
2.75 

1.88 
0.13 
0.63 
5.43 
25.14 
3.57 
26.13 
3.29 
24.14 
7.00 
21.86 
4.13 
5.25 
0.25 
0.25 






1/Growth clipped on April 3. causing considerable mortality of immature 
larvae. 
THE PUPAL STAGE 
The pupal stage (fig. 1. E) is passed in thin, white, netlike cocoons, 
usually oval in shape. Mature larvae usually attach their cocoons to the 
growing leaves of host plants. One or more leaves may be utilized to pro- 
vide satisfactory protection during this state of inactivity. A considerable 
number are also attached to dead leaves and stems above the ground. Com- 
paratively few are spun in the surface litter or on the bare soil. The 
spinning of cocoons above the ground is not a seasonal habit but a charac- 
teristic of the species. In this respect H ypera brunneipennis differs from 
the alfalfa weevil (H. postica ) , which spins most of its cocoons in the sur- 
face litter. 
Shortly after spinning, the larva curls up and remains relatively in- 
active during a short period in which it gradually transforms into a pupa, 
UBRARY 
OTATC PU^T BOARD 
