October, '15] SWEZEY: insects in the HAWAIIAN ISLANDS 



453 



Lantana Insects 



Another phase in the introduction of beneficial insects was the 

 introduction of the lantana insects by Mr. Koebele in 1902. He made 

 a thorough study of the insects preying exclusively on lantana in 

 Mexico, to ascertain which could be safely introduced to serve as a 

 check on this plant in Hawaii. Among the many species of insects 

 studied, eight were successfully introduced and finally spread all over 

 the islands. Of these insects, the maggots of the little black seed-fly 

 (Agromyza sp.) destroy the seeds in the growing berries; the larvjB of 

 two moths (Platyptilia pusillidactyla and Crocidosema lantana) feed in 

 the flower clusters, thus helping to prevent the formation of fruit; the 

 caterpillars of two butterflies {Thecla echion and Thecla agra) feed on 

 the flowers; the larvse of a tiny moth {Creynastobomhycia lantanella) 

 mine the leaves, thus causing them to become ineffective in the service 

 of the growing plant; a small bug (Teleonenia lantanw) feeds abun- 

 dantly on the underside of the leaves, causing them to die and fall 

 off; a gall-fly {Eutreta sparsa) produces large swellings or galls on 

 freshly-growing shoots, thus checking the normal growth. 



The growth of lantana has been greath' checked by all these 

 insects, and in some places their effect, in connection with climatic 

 conditions, has killed it off entirely. The greatest benefit derived 

 has been from the destruction of the flowers and seeds, so that land 

 once cleared of lantana does not again become invaded by it; whereas 

 formerly on the cattle ranges a great deal of expense was involved 

 in continuously rooting out lantana, for it was always being reseeded 

 by birds dropping the seeds broadcast. Now, very few seeds are 

 formed, as many of the flowers are destroyed by the larvae of the two 

 butterflies and the two moths above mentioned, and what seeds do 

 start to grow are mostly eaten by the larvae of the Agromyzid fly. 



There has been considerable fear on the part of some that the intro- 

 duced lantana insects would become pests on other plants, especially 

 when the lantana became scarce or killed out, but such has not been 

 the case. None of these insects have ever become injurious to any 

 cultivated fruit or plant, and it is indeed doubtful if any such plant 

 has been in the least attacked by them. It is of interest to note in 

 this connection that at the time the Mediterranean fruit-fly first be- 

 came knowm in Honolulu, an opinion expressed by many of those igno- 

 rant of the ways of insects, was that the ''lantana fly" had changed its 

 habits and turned into the fruit-fly, thus becoming a bad pest. Some 

 were so thoroughly imbued with this idea that it was impossible to 

 convince them of their error. 



