NEUROPTERA 



35 



Psocidae are richly represented in the islands and twenty-five species are dealt with 

 in the present paper. No doubt many others yet remain to be discovered, indeed other 

 species are certainly included in those collected by me, but owing to their small size 

 and poor state of preservation it was not advisable to attempt the description of the 

 species. Nearly all are subject to much distortion and contraction of the body-segments 

 after drying, as well as discoloration, and owing to the exudation of a sticky substance 

 they are with difficulty relaxed, so as to be suitable for examination. Evidently there 

 are good characters in the terminal abdominal segments of the ^, but these are not 

 available in dried examples. Many of the species exhibit great variability (in colour, 

 nervuration, etc.), which is so remarkable a feature of so many Hawaiian insects. The 

 difficulties of study in this group are so great from the causes above enumerated, that 

 the present paper on these insects can only be regarded as a preliminary sketch, especially 

 as regards the species referred to the genus Elipsocus, in which the instability of 

 nervuration is so great, as to render the discrimination of species almost hopeless, without 

 special attention to the insects in the field. In this preliminary study I have not con- 

 sidered it advisable to enter minutely into the generic question, but have referred all 

 the species to three well-known genera. The solitary species referred to Stenopsocus 

 temporarily, is clearly generically distinct therefrom, but only one example, in mutilated 

 condition, was secured. It is very different to any other Hawaiian Psocid, and is inter- 

 esting as having been taken at a high elevation in the mountains, where the nights, 

 even in August, were cold, with hard frosts. Of the other 24 species, 14 are assigned 

 to Psocus, most species of which appear to be confined, each one, to a single island, 

 while 10 are placed in the genus Elipsocus. Some species of this latter genus are 

 so variable in nervuration, that not only generic, but even characters of superior value, 

 are affected. 



The other components of the Neuropterous fauna are comparatively of little interest. 

 The two Termites belong to the genus Calotermes. The smaller of these, C. margini- 

 pennis Latr.,i is certainly an introduced species and has done great damage to wooden 

 buildings in the city of Honolulu. The larger one, referred to C. castaneus Burm., is 

 very possibly distinct from that species, which was described from winged forms. The 

 soldiers of the Hawaiian species possess well-developed eyes, and it is noteworthy that 

 they are found (and probably only found) in the native forests, and series of them 

 from three of the islands vary distinctly in the length of the gular area on the under-side 

 of the head, as though they were already forming distinct races on the various islands. 

 It is possible however that this variation, although affecting an important character, is 

 merely such as occurs in different communities, and is not due to isolation on different 

 islands, the material at hand not being sufficient for deciding this point. 



The solitary Embiid {Oligotoma insularis M'Lach.) is an interesting insect on 

 account of the dorsal sclerites of the thorax in the winged Z not being of the simple 

 structure usual in these insects, and very different to those of the apterous ?. An 



