BIOLOGIC NOTES ON SPECIES OF DIABROTICA. 
81 
The extreme minimum of 29 degrees occurred only on one or two 
days during "northers," and excepting those few days the minimum 
did not get below 40 degrees. During April and May the range was 
from a minimum of 46° F. to a maximum of 95.5° F. The average 
temperature during these five months was as follows: 
Average temperatures at Brownsville, Tex., from January to May, 1909. 
1909. 
Average 
maxi- 
mum. 
Average 
mini- 
mum. 
January 
February 
March 
° F. 
75.3 
75.7 
81.7 
82.5 
85.0 
o F 
56.1 
55.0 
60.0 
65.2 
70.5 
May 
The following description of the earlier stages was prepared by 
Mr. McMillan from living material: 
DESCRIPTION. 
Egg. — Pale yellow, oval and regularly elliptical, very finely sculptured, about 0.6 
mm. long by 0.33 mm. wide. 
Newly hatched larva. — Pale yellow, head light brownish, anal segment light gray. 
Slender, with head and thoracic segments broader than rest of body, except anal 
segment, which is covered by a shield flattened and rounded at posterior margin. 
Body sparsely covered with short, colorless hairs which in length are about one-half 
diameter of body. Length, 2.25 mm.; width, 0.25 mm. 
Mature larva. — Light yellow, head and anal plate light brownish. Body slender, 
dorsal and ventral surfaces smooth, longitudinal wrinkles provided with scattered 
hairs on lateral surfaces. A few short hairs on head and anal segment. Head slightly 
longer than wide, flattened. Length, when extended, 12 mm.; width, 1.25 mm. 
Pupa. — Light yellow, concolorous. Body rather long, oval in general outline, 
abdomen tapering slightly. A few scattered hairs on head and abdomen. A pair of 
stout spines on dorsal surface of anal segment and a pair of fleshy tuberclec on ventral 
surface of same. Length, 5 mm.; width, 2.5 mm. [D. K. McMillan]. 
EXPERIMENTS WITH REMEDIES. 
Arsenate of lead appears to be an excellent remedy for this pest, 
as is shown by the following records: 
During November, 1908, Mr. McMillan sprayed one-tenth of an 
acre of tomatoes, which were being damaged by this Diabrotica, with 
arsenate of lead at the rate of 6 pounds to 100 gallons of water, and 
with pyrox, a commercial brand of combined arsenate of lead and 
Bordeaux mixture, at the rate of 8 pounds to 100 gallons. The results 
from both insecticides were very good, no differences being noted 
between them. 
February 8, 1909, a patch, about one-twentieth of an acre in 
extent, of tender-leaved string beans was being rapidly defoliated 
by this species at Brownsville, Tex. With the exception of two 
