BIOLOGIC NOTES ON SPECIES OF DIABBOTICA. 83 
were found to have been scraped nearly bare, and in a few cases the 
larvae had buried themselves in the main root. All observed were 
nearly mature. One larva made a cell April 17, pupated April 21, 
and the adult developed April 28. Other beetles developed April 30 
and May 1 . 
During May beetles were observed, but no injury was noticed or 
reported. 
June 10 the beetles were abundant at Mcxlllen, Tex., feeding on 
the foliage and rinds of watermelons and disfiguring some of the 
melons. The foliage in some places was badly riddled, but the crop 
was so far advanced that this caused little damage. Many beetles 
hid during the middle of the day among cabbage and Amaranthus 
leaves for protection from the sun. 
The life history of one generation of this species was worked out 
as follows: 
Record of a single female of Diabrotica vittata placed in confinement April 26, 1909. 
April 26 Placed in confinement. 
May 2 42 eggs deposited. 
May 10 42 eggs hatched . 
May 21 First larvae made cells. 
May 24 First larvae pupated. 
May 29 First adults developed. 
May 30 First adults issued. 
June 2 All adults had issued. 
The stages were as follows: 
Days. 
Egg stage 8 
Larval stage 14 
Pupal stage 5 
Total 27 
The mature larvae were in the cells three days before pupating and 
the adults remained in the cells from one to four days before issuingo 
The first pair of these beetles mated June 4. and the first eggs, 20 in 
number, were deposited June 11. 
On May 3 another female deposited 58 eggs and the following 
record was obtained: 
Days. 
Egg stage 7 
Larval stage 15 
Pupal stage 5 
Total 27 
During the first weeks of May, when this species was being reared, 
there was a period of excessive humidity. The larvae were supplied 
with sections of cucumber vine as food. The humidity caused this 
food to decay very rapidly and this necessitated frequent renewal, 
and as a result many larvse died and only a relatively small propor- 
tion was carried to maturity. The temperature during May, 1909, 
