Correlation between boll weevil development and mean temperature. -- 
T, C, Barber, Brownsville, Tex., has been rearing boll weevils through 
out the winter from field-collected cotton squares. The lower part 
of the Rio Grande Valley is probably the only locality in the United 
States where a continuous supply of infested cotton squares would be 
available to the boll weevil under natural conditions throughout the 
winter. From his studies of boll weevil development during eS winter 
of 1933-34, Mr. Barber erie the following conclusions: ae 
"], If the mean peace falls as low as 52° F., there will 
be no weevil emergence until the temperature again rises. 
to, If the minimum temperature falls as low as 40° F., there 
will be no weevil emergence the following day, even though the maximun 
temperature should rise sufficiently to raise the mean temperature as 
high as 59° F 
"3, If the mean temperature falls as low as 60° F., or lower, 
accompanied by a drop in relative humidity to 50 percent or less, there 
will be no weevil emergence, 
"h, But with a mean temperature of 55° F., and a relative humidity 
of 80 percent, a slow emergence of boll weevils will continue, indicat- 
ing slight weevil activity. 
"5, Irrespective of relative eeopickien it is definitely indicated 
that a mean temperature of about 54° F. is the teetering point of boll 
weevil activity, with the percentage of relative humidity acting as the 
balancing medium. With a high percentage of relative humidity at this 
point there will be slight weevil activity; with a low percentage of 
humidity there will be no activity." 
Notes on cotton flea hopper.--K. P, Ewing, Port Lavaca, Tex., 
reports that the first cotton flea hoppers (Psallus seriatus Reut.) 
hatched on February 12 from overwintering eggs in stems of plants 
placed in hibernation cages. This is two days earlier than in 1933; 
however, the hoppers did not appear in numbers until about the middle 
of March, which is considerably later than last year and is due to 
the cooler weather this spring. The mean temperature this March was 
483° F, lower than in March 1933. The first nymph found in the field 
was of the second instar and was taken on March 6, Field inspections 
show that the flea hopper nymphs are very scarce, as compared with 
the number present at’ this time last year. Horsemint, a favorite 
spring host plant, sprouted early but because of the cold weather has 
made very slow growth. Croton plants are scarce and also very small, 
as compared with last year, 
