INTRODUCTION ccxvii 



that it continues to be brought here by commerce. Sometimes this cricket forms a 

 large part of the food of the mongoose. A second species of Gryllus appeared in the 

 islands in 1900 and is now at times extremely common on Oahu. Gryllodes poeyi is 

 abundant in many places, and is often found beneath rocks in extremely dry situations. 

 It also is a lowland, or at least not a forest insect. The imported mole-cricket {Giyl- 

 lotalpa africana) is, so far as is known, still confined to the island of Oahu and has 

 acquired an unpleasant notoriety, as being decidedly injurious. The injury done by this 

 insect is of two kinds. Burrowing in the banks of ditches etc. it allows the water, used 

 for irrigation purposes in cane- and rice-fields, to escape, and also, locally, seriously 

 injures the stems of growing sugar-cane, where they lie on the ground, by driving 

 large borings or tunnels through these. It is e.xcessively numerous in suitable localities, 

 and on hot dark nights, during the prevalence of southerly winds, is occasionally 

 attracted in countless numbers to the lights of lighthouses and other less powerful 

 lights. 



The little myrmecophilous cricket is common on Oahu in the nests of various 

 foreign ants, such as Pleidole megacephala, Solenopsis geminata and more than one 

 species of Prenolepis. In migrations of some of these ants we have observed these 

 crickets marchingf in line with their hosts. We have also found them in nests of ants 

 brought in consignments of growing plants from foreign countries, when examining 

 such consignments on the wharf in Honolulu. 



The endemic Grylloids belong to two different groups, the Trigonididae, repre- 

 sented only by the genus Paratrigonidium, and an endemic family or tribe Prognatho- 

 gryllidae, in no way related to the former, and containing several distinct genera. The 

 Hawaiian species of Paratrigonidijini are remarkable for the fact that while they severally 

 often exhibit very great distinctness in habits, in structure and appearance they often so 

 closely resemble one another as to be only separable with great difficulty and by very 

 slight characters. All are true forest insects. P. pacificum, commonest and most 

 ubiquitous of all the species, is chiefly terrestrial in habits. Though occasionally it 

 ascends ferns, bananas, etc., it is mostly found actually on the ground in damp places 

 and moves about actively by day in the deep shade. Many of the other species are 

 strictly nocturnal, living in concealment and remaining silent by day, whereas P. pacifi- 

 cum sings the whole day through, as well as at night. P. gj'ande and P. atte^uiatum are 

 commonly found beneath bark of trees, often in mixed assemblages of young and old 

 together. P. saltator and freycinetiae live only at the bases of the leaves oi pTeycinetia, 

 P. roseum, subroseum and atroferrugineum only amongst the leaves of Metrosidertis ; 

 the latter, indeed, has only been found on one special variety of this tree ! P. filicum 

 and viridesccns are found on ferns, each frequenting different kinds, and so not mixing 

 together. In general, the young of the species that frequent foliage are green, however 

 differently coloured the adults may be, whereas those that live on the ground or beneath 

 bark of trees, have brownish or obscurely coloured youngf. The terrestrial P. pacificum 

 F. H. I. ee 



