34 GUAM AGRICULTURAL EXPERIMENT STATION. 



fiyrj)hi(l fly, Xanthogramma grand icor-nis, and of a hemerobiid feed 

 oil i)l:uit lice. Xanthogramma. however, is parasitized and so its 

 utility is greatly reduced. There is also a common chrysopid the 

 larva of which preys on plant lice and other small-bodied insects. A 

 forficulid, Ch-elisoches fnorio, has similar habits. A carabid, Chlfpnini^ 

 hi(/i/.ffatus, is very active about vegetable patches as a caterpillar 

 predator. A eumenid wasp, RhyncJi'mm sp., gathers caterpillars as 

 food for its young and in this way must be considered a very bene- 

 ficial insect. Three common vespids, one a Polistes, also destroy 

 many caterpillars, and there are one or two tachinid flies parasitic on 

 caterpillars, but specimens were not secured in breeding. There are 

 numerous species of dragonflies, which hawk the air in search of 

 small-bodied flies and play a very efficient role in the reduction of 

 mosquitoes. The honey bee, introduced some years ago from Hawaii, 

 is a very common insect in Guam. Many hives are maintained, but 

 they as a rule are poorly cared for. Species of Gonatopus, leaf hopper 

 parasites, Parasierola, and Trichogramma were also secured without 

 learning the host relation. 



Some very common insects in Guam not mentioned above are the 

 milkweed butterfly, Anosia plexippus; the mole cricket, Gryllotaljja 

 africana^ which often becomes a pest, since it feeds on the roots of 

 various plants; and the vinegar fly, DrosopMla ampelophila. 



In comparison with some other tropical regions where the insects 

 have been studied, the island can be said in a general way to have few 

 injurious insects, although its undeveloped state leaves one rather in 

 doubt. This statement, however, is made merely to emphasize the 

 importance of a strict quarantine of plant introductions. A large 

 number of the present injurious insects are insects which have been 

 introduced on plants or plant commodities and many more will in- 

 evitably come if plant introduction is not discouraged or whatever is 

 brought in is not thoroughly examined, cleaned, and fumigated. 

 While the writer was in Guam, Japanese beetles {Adoretus tenuima- 

 culati/s) and other pests in a consignment of plants from Japan were 

 intercepted in quarantine. This matter has been brought to the atten- 

 tion of the Government and a regulation issued covering it. The con- 

 tinuation of the present happy condition of a meager fauna depends 

 largely on the thoroughness with which this regulation is enforced. 



The introduction of insect predatoi-s and parasites of local injurious 

 insects is an important line of work. A^Hiile the writer was on the 

 island an attempt was made to introduce a coccinellid beetle, Crypfo- 

 Icemus montrovzieri, a very efficient mealy-bug feeder in Hawaii. 

 Out of a lot of several hundred sent, about 40 or 50 were liberated 

 near the office building and a new generation had appeared before the 

 writer left. Hymenopterous parasites of dungflies from Hawaii, 



