INSECTS AND OTHER ANIMAL Pests INJURIOUS TO FIELD BEANS 1003 
3 
The writer has not succeeded in rearing these larvae, but it is believed that 
the insect hibernates in the larval stage near the roots of its host plants. 
On May 25, 1920, larvae of what is believed to be this species were found 
around ragweed, but when these were taken to the laboratory for rearing, 
they died. Later, pupae of S. taeniata were found in this same place. 
It seems reasonably certain, then, that the larval stage normally begins 
between the last of July and the middle of September, and does not end 
until late May or early June of the following year. This would make a 
larval period of from nine to eleven months. In 1886 Forbes (1894) 
found larvae feeding in young corn plants in Illinois on May 17, and again 
on July 11 and 12. Chittenden (1903) reports finding larvae feeding on 
the roots of lamb’s-quarters and Jamestown weed. 
The pupa 
Pupae of Systena taeniata were found from June 29 to July 12, 1920, 
around dead ragweed along the edge of a field that had been in beans the 
previous year. Twenty were ,discovered about one plant, three inches 
below the surface, in rather compact soil. Beetles emerged from these 
pupae between July 13 and July 25. Forbes (1894) reports pupae emerg- 
ing on May 26 and June 7 from larvae found on May 17. Adults from these 
pupae emerged by June 17. It would appear, then, that the pupal stage 
may cover from two to three weeks. : 
The adult 
Pale-striped flea beetles have been taken in the field from the middle of 
June until the middle of September. In 1920 the first beetle was seen on 
June 19 and a few were alive in cages on September 10; the maximum 
number was present on plants about July 20. The ovaries of female beetles 
opened on June 29 were very immature, but many well-developed eggs were 
found in insects dissected on July 21. 
It has been noticed each year that when Systena taeniala becomes scarce 
on beans, beetles may still be found on ragweed and lamb’s-quarters, 
especially along the edges of fields. On August 19, 1920, taenzata was 
becoming scarce on beans, but it occurred in large numbers on its weed 
hosts until about September 3. 
During the latter part of their adult life, the females go down into the 
ground around their favorite food plants to deposit their eggs. In search- 
ing for eggs, the writer has often found the beetles crawling in the dirt three 
inches below the surface. One much battered female was found four 
inches down in the ground, near a ragweed plant, on September 16, 1919, 
when most of the beetles had disappeared. On September 23, 1919, a 
beetle with particles of dirt adhering to its legs and its wing covers was 
found on ragweed. It had apparently been down in the ground, had de- 
posited its eggs, and had come up again to feed. 
