20 INSECTS INJUKIOUS TO SUBTROPICAL FRUITS. 
infested, and in such cases the larva? move around to the other side 
and feed. Thus the function of the leaf is entirely destroyed and 
the leaves dry up and often fall. (See PL IV.) In feeding, this thrips 
excretes over the surface of the infested leaves a reddish fluid in small 
spots, which hardens and turns black. Although it has not been 
observed on the fruit, it is probable that in cases of severe attack this 
insect will also attack the fruit of the mango and avocado in the same 
manner that it does the pods of cacao. If such a condition should 
result, it will produce even greater loss, since the value of these high- 
grade fruits will be greatly reduced. The effect of the feeding is 
graphically shown in Plate IV, where the leaf on the left is uninjured 
and the leaf on the right has been infested by thrips. 
ORIGIN AND DISTRIBUTION. 
Heliothrips rubrocinctus was originally described from specimens 
collected in the island of Guadeloupe, French West Indies. At about 
the same time it was observed to be injuring cacao on islands of the 
British West Indies — Grenada, St. Vincent, St. Lucia, and Dominica. 
Maxwell-Lefroy, in Indian Insect Life, wrote: "Physophus rubrocincta 
Giard is a serious pest to cacao in the West Indies, to which place 
it was probably introduced from Ceylon." There has been some 
question as to whether the thrips which injures cacao in Ceylon is 
this same species, but as the author quoted above was one of the 
first to study this species in Grenada it is hardly probable that he 
would mistake another insect for it, provided he saw the insect in 
Ceylon that he refers to this species. 
This thrips occurs also in Trinidad, the island of Tobago, the Virgin 
Islands, and the L T ganda, and within the past year has been recorded 
from the Hawaii Experiment Station greenhouses in Honolulu. 
In the United States it is confined to a short strip of the Florida 
east coast centering in Miami. As it is a tropical species, it will 
probably not spread north of Florida; therefore, unless it obtains an 
entrance into California or into greenhouses in the North the distribu- 
tion in our own country will be limited. This insect has been taken 
in one of the greenhouses of the Department of Agriculture on plants 
from Mauritius. At present it is quite widely distributed in the 
tropical islands of the Atlantic and Pacific Oceans, and its original 
home was, without a doubt, in some of these islands. It may have 
first come from Ceylon, as Maxwell-Lefroy suggests, or its original 
home may be in the West Indies. Its habitat is the Tropical Life 
Zone, as designated by Dr. C. Hart Merriam.° 
a Life Zones and Crop Zones of the United States. Bill. 10, Biol. Snrv., U. S. Dept. Agr., 1898. 
