INSECTS AXD DISEASES QI 



onion thrip occurs in the following localities : 

 Russia, Germany, Bermuda, Connecticut, New York, 

 New Jersey, Pennsylvania, Virginia, Ohio, Illinois, 

 Colorado and California. To these should now be 

 added Florida. It is doubtless of European origin, 

 and has been brought over in some shipment of onions 

 or cabbage. The insect was first made known to 

 science by Dr Londeman of Moscow^ who found it 

 very destructive to tobacco in southern Russia. 



"The egg of this species is almost colorless, elon- 

 gate, and curved. The egg state lasts from three and 

 a half to four days. Upon hatching, the larvae are 

 quite agile, running about readily if disturbed. They 

 are almost transparent in color but become gradually 

 of a greenish-yellow color, the greenish tint due doubt- 

 less to the contained food. These larvae are somewhat 

 gregarious in their habits, and may be seen feeding 

 together in groups. They use the spines on the end 

 of the abdomen to drive away intruders, by striking 

 right and left. In almost all cases it has the desired 

 effect, and the victim seems glad to get away. The 

 larval stage lasts from seven to nine days. The 

 nymph stage lasts for four days, the insect remaining 

 almost in the same tracks throughout the period, if 

 left undisturbed. No food is taken. 



"The third and last molt of the insect is from the 

 nymph to the adult condition. A newly developed 

 adult is quite light in color, and does not acquire the 

 normal color for twelve to fifteen hours. The length 

 of life of an adult was not satisfactorily determined. 

 Specimens were kept, however, for nearly three days, 

 when they met with an accident. From the above it 

 will be seen that the total life cycle of the insect in 

 Florida is approximately sixteen days. ... In 

 Florida there are probably no distinct broods, as all 

 stages may be found at the same time. Allowing for 



