cxcviii FAUNA HAWAIIENSIS 



all stao-es these bugs of restricted habitat most closely resemble parts of the plants 

 on which they are found. 



Others that have not so special a habitat, yet often occur in their greatest numbers 

 in situations, which best serve to conceal them. I have observed scores of R. oscillans, 

 in all stages, on dead or dying fern fronds with which their colours harmonized very well. 



The flightless species of the sub-genus Nesotyphlias, are much more terrestrial in 

 their habitats than the others, some in fact, so far as is known, live entirely on the 

 ground. They ascend ferns especially, on occasion, but are not at all arboreal as the 

 fully-winged group are. 



The nymphs of Reduvioins are not as a rule of particular interest ; the basal 

 antennal joint, which usually becomes much more slender in the adult, than it was in 

 the nymph, in R. kcrasphoros increases in thickness in the adult, in which also the 

 processes of the head become much larger than in the penultimate stage. In young 

 nymphs these curious horns are absent. 



The Hawaiian Reduvioli prey upon small and weak insects and we have never 

 seen them attack Coleoptera, as the introduced Zelus does. It is probable that the 

 comparative feebleness of their mouth parts would render this impossible. They are 

 commonly found on such plants, as are the home of small Delphacid leaf-hoppers, on 

 which they are well known to feed, while some of them eat also the honey-dew or 

 sweet excretion that is produced by the hoppers. They have been seen sucking the 

 juices of Psocids and it is probable that these form an important article of diet of 

 several species. The imported leaf-hopper {Perkinsiella) which did so much damage 

 in the cane-fields, was attacked to some extent both by R. capsiformis and R. black- 

 burni, both becoming common in some of the affected fields. 



The eggs of R. capsifoinnis are destroyed by the Mymarid parasite, Polynema 

 reduvioli. In 1902 leaves of melon plants, very badly attacked by an Aphis, were sent 

 to me for inspection, and on these were many nymphs and adults of R. capsiformis, 

 preying on the plant-lice. The eggs of the Reduviolus, however, had become very 

 highly parasitized by the Polynema, very few young bugs appearing. Embedded 

 in the leaves of grasses and of the sugar-cane eggs from which parasites have escaped 

 are found not infrequently. Probably the eggs of species of the terrestrial, flightless 

 sub-genus Nesotyphlias will likewise, when discovered, be found to yield a Mymarid 

 parasite, for a large Polynema is constantly observed flying over the earth, in the damp 

 dark haunts of these insects. Further it is possible that these parasites are a strong 

 check on the multiplication of Hawaiian Reduvioli in general. 



Gerkidae. — A family of small importance represented by two genera, each with a 

 single species, one of which, Halobates sericeus, is of very wide distribution, and has 

 been seen on the sea round various parts of the coast of several of the islands, and no 

 doubt occurs round all. I have seen Halobates in great numbers, when I have been 



