140 IOWA STUDIES IN NATURAL HISTORY 
Pools of stagnant water are frequently met with and even some of 
the plants harbor sufficient water among their branches and stems 
to allow the pests to breed. One of the most interesting places in 
which I discovered mosquito larve was among the bases of the 
stalks of a large-leaved plant (Cyrtospermum edulis) which looks 
something like our rhubarb. Mosquitoes of the malaria-carrying 
genus Anopheles are not found on the islands but the dissemina- 
tors of yellow fever and filariasis (Stegomyia fasciata and Culex 
fatigans) are present in some numbers. Although I saw only a 
single instance of the disease known as elephantiasis, the form in 
which filariasis is most often exhibited, I was informed by the 
physician who has charge of a large general hospital at Navua, 
that this disease is widely prevalent in the Fijis. 
Flower flies (Syrphide) are common, the genus Xanthogramma 
being well represented. <A large horse fly (Tabanide), Tabanus 
fijianus, with yellow and black abdomen sometimes attacks human 
beings. 
The fruit-flies (Trypetide) are represented by several species, 
one of which, Dacus parsiflore, in the larval stage, attacks the 
fruit of several plants and causes some damage. Another small 
form with heavily-veined wings (Oxyna parca) is common. 
The order Hymenoptera (four-winged flies, ete.) is exceedingly 
well represented but ants make up the largest share of the group. 
The large yellow vespid (Polistes hebreus) is common every- 
where and its pensile paper nests are often constructed in mula- 
mula trees and in bamboo thickets. On one occasion I inadvertent- 
ly aroused a colony of the wasps in such a situation and, having 
heard of their effective defensive ability, I considered retreat the 
better part of valor and acted accordingly and hastily. At Colii 
Suva where extensive road surfacing was being done under the 
direction of Mr. Dawson Thompson, a European engineer, these 
insects caused no end of trouble by insisting on crawling into his 
rolled-up maps and tracings while they were resting on the 
shelves in his shack. 
A, number of the smaller representatives of this order are of 
value as natural checks on destructive insects by parasitizing their 
eggs or larve. 
Ants are everywhere and exceedingly abundant in number of 
individuals while the number of species, as already indicated, is 
large. The formicid, Pheidole megacephala, is a general predator 
