THYSANOPTERA 673 



and Agnostochthona except from Kirkaldy's description, from which Agiwstoclitlwiia 

 would appear to be an Antlwtlirips, and Nesothrips would appear to come near 

 Oedemoih?'ips ; the species of the genera Trichofhrips, Anthothrips and Thrips are 

 world-wide in their distribution. 



A large proportion of species are each peculiar to one particular island ; such are 

 denoted in the table by their names appearing in black type instead of in italics. Now, 

 probably owing to the comparative paucity ot material, we have had to describe 

 a number of unique types (these being denoted by an "m" in parenthesis), but even 

 taking these into consideration we find several outstanding features worthy of note, 

 though we are not yet in a position to make generalisations with any degree of 

 certainty. The first and perhaps most striking feature is in the distribution of Dermo- 

 thrips. The wingless form is found more or less commonly in three islands, including 

 the two most widely separated islands, Kauai and Hawaii, whilst the winged form is 

 found in a fourth island, Oahu. No winged examples have been taken in any one of 

 the islands where the wingless form occurs, whilst the winged form which is larger and 

 more robust than the wingless form, is peculiar to Oahu, where the wingless form is 

 unknown. We might, in fact, regard this macropterous form as a distinct local race. 



The preponderating genus is Dolerotlirips, and of the nine described species seven 

 are confined each to a single island, whilst lanaiensis is, one might almost say, peculiar 

 to Lanai, as the specimens recorded from Molokai and Hawaii are referred to that 

 species with some little doubt. D. dubins occurs in the same islands as lanaiensis. 



Neither Dolerothrips nor any of its allied genera is represented in Kauai, in fact 

 Dermothrips is the only Tubuliferon we are able to record from that island ; but three 

 Terebrantians (in two cases, if not all, introduced) occur, these same species being found 

 again in Hawaii. 



So far we can only regard Heliotlirips JiaemorrJioidalis, H. rnbrocinctiis and 

 Limothrips cerealiimi, and more doubtfully Anthothrips icsitatns, Scolothrips d-macitlatus 

 and Thrips viultispiniis, as important from an economic point of view. 



It is unfortunately certain, however, that more of these little pests exist, and 

 unknown and unseen are causing damage in a greater or less degree upon the various 

 valuable crops that are being cultivated in the Hawaiian Islands. 



As an illustration of the decided economic importance of the Terebrantian 

 Thysanoptera we might instance the Pear thrips, Euthrips pyri Dan. In 1895 this 

 species appeared in such great numbers as to cause extensive damage to hundreds ot 

 acres of orchards in California, and ever since then it has occupied the attention of 

 several American economic entomologists. Only last year we recorded its appearance 

 in Great Britain', and within a year of its appearance we learn that much damage has 

 been done to many pear and plum orchards in the south of England. Like most, if 

 not all Thysanoptera, E. pyri is parthenogenetic, and in the countless thousands of 

 Californian specimens examined not a single example of the male has been discovered ; 



' Bagnall, Journal of Economic Biology, lv. pt. 2. 



