SEASONAL HISTOKY AT COMPTON, CAL. 31 
When this weed first comes up in the early spring there is scarcely 
any vegetation, so that it offers an agreeable host to the bean thrips, 
especially as the foliage is very tender and juicy at that time. The 
thrips attack the first young leaves, and the larvae, upon hatching 
from eggs deposited at that time, join the feeding adults. As soon 
as these become abundant, the leaves lose all or nearly all of the green 
leaf -content and turn white, after which they dry up and hang dead 
from the stalk. The infestation continues to spread to the younger 
leaves until the entire plant is killed. 
The sow thistle (Sonclms oleraceus) has the same general distri- 
bution and is also a favorite food plant. 
Wild heliotrope (Heliotropium' curassavicum) is another favorite 
food plant late in the year. This plant does not start in the spring 
until quite late, and when it does appear above the ground generally 
escapes destruction by cultivation. Thus it occurs commonly in the 
beet and bean fields and in orchards, and in the fall is one of the 
chief food plants. 
The bean thrips has also been found feeding and reproducing in 
numbers on Euryptera lucida and on one of the cucurbitacese, prob- 
ably an Echinocystis, in a canyon north of Los Angeles. In the same 
locality it was later taken feeding and reproducing on Gnaplialium 
calif ornicum, Mirdbilis calif 'arnica, E unarms brevipes, Chenopodium 
murale, Helianthus annum, Atriplex sp., wild turnip, Erigeron cana- 
densis, and wild pea (Lotus americanus). It was also taken in the 
valleys feeding and reproducing on the Chinese cigarette flower (Nic- 
oliana glauca), Bidens pilosa, Verhascum virgatum, Polygonum avi- 
culare, and Crepsis (?) sp. The adults were also taken in the fall 
feeding on the foliage of a porch vine, Tacsonia mellissimus, and on 
the cultivated nasturtium (Tropceolum major). Mr. A. C. Morgan 
found it on the underside of the leaves of the tulip poplar at Clarks- 
ville. Tenn. 
This thrips has also been recorded as feeding on Lotus glaber, 
apple, peach, orange, wild vetch, burr clover, and radish. 
After perusal of the above list of food plants it is easy to see how 
this insect . can obtain a foothold in a cultivated crop in the late 
summer, especially as many of the wild plants die from maturity or 
lack of moisture, thus forcing the insect to migrate. 
SEASONAL HISTORY AT COMPTON, CAL. 
The life cycle of the bean thrips was observed at Compton for vary- 
ing parts of the year, and because of the cooler and more even tem- 
perature prevailing there is quite extended and more nearly equal 
for the entire period of reproductive activity. 
THE EGG. 
The length of time required for the egg to hatch in the months of 
March, April, and May was not exactly determined. However, fresh 
