16 BULLETIN 889, U. S. DEPARTMENT OF AGRICULTURE. 
each time, so that the tip of the abdomen approached the excavation at each deposi- 
tion, and then again to the rear, so that the jaws would strike the excavation when 
about to prepare a place for the next egg. Thus, in preparing the cavity, the beetle 
was facing up, with her body below it; when about to deposit the first egg she simply 
moved forward the length of her body, and afterwards simply wheeled in her tracks, 
when about to prepare a place for the second egg. The succeeding depositions were 
executed by wheeling about each time. Therefore, each completed movement, 
consisting of two wheels to the rear,.accomplished the deposition of two eggs, 
occupying about 44 minutes. 
SEASONAL HISTORY. 
A study of the seasonal history of this insect in the southwestern 
United States is especially interesting because of the bearing it has 
upon the control of the species. 
There is present, especially in the Salt River Valley of oe 
along ditch banks, fence rows, and all waste places in the spring of 
the year, a luxuriant growth of yellow sweet clover (Melilotus offi- 
cinalis) (Pl. I, fig. 1). Hibernating beetles, upon their appearance 
in early March, find this sweet clover growing in the immediate 
vicinity of their winter quarters, and consequently, when the repro- 
ductive instinct asserts itself, they begin ovipositing in this plant, 
the growth of which is at the proper stage for their purpose. The 
_ first generation of these beetles is, therefore, passed almost entirely 
upon this plant. 
The date of emergence of the beetles depends quite largely upon 
conditions of temperature. During the spring of 1915, on March 12, 
beetles were found by the senior author to be still hibernating and 
they did not begin their activities for at least 10 days following this 
date. Durimg 1916, on the other hand, eggs were found in yellow 
sweet clover by the junior author on March 9, and in the same year 
larve were taken in the field on March 15. The average mean tem- 
perature, at Tempe, Ariz., from February 1, 1915, to March 12, 
1915, was 52° F., while the average mean temperature from Feb- 
ruary 1, 1916, to March 9, 1916, was 59° F. 
In the eastern United States this beetle has only one generation 
annually. A review of observations by several writers shows that 
hibernating beetles come forth in late April or early May, eggs are 
deposited soon thereafter, and by late June larve are usually abun- 
dant. By August 1 pupz are present and in early August the new 
adults begin to appear. These continue to emerge until late Sep-— 
tember, and soon after the appearance of heavy frosts the species 
is again in hibernation. | 
This insect in.the southwestern United States has three distinct 
generations annually. As has already been mentioned, the first gen- 
eration is passed almost exclusively upon yellow sweet clover, while 
the second and third generations are passed upon alfalfa and other 
plants, the majority of which are weeds. Where alfalfa is found, in 
