290 FAUNA HAWAIIENSIS 



Derobroscus and Brosconymus, pp. 197, ^98. Though these insects are most 

 difficult to procure it is probable that they are, or have been, really abundant, and 

 that their habits protect them against the collector. Of the four .species Mr Perkins 

 has only been able to find eight specimens during his ten years in the islands. Mr 

 Blackburn, who worked principally in Oahu — the only island on which these forms 

 occur — did not discover their existence. Unlike the preceding genera, all of which 

 are terrestrial, the species of Derobroscus and Brosconymus are arboreal in habits, 

 living for the most part concealed in holes or in the twigs, and extending apparently 

 to any part of the tree that is suitable in its condition. This habit has not pre- 

 viously been recorded for Carabidae, though it is not improbable that it may be 

 subsequently discovered to occur not infrequently in tropical forests. 



Though this habit (combined with the possibility that these insects may be partially 

 nocturnal in their activities') protects the Derobroscus from the collector, it has failed 

 to afford them a perfect protection from birds ; of which indeed they appear to be 

 a favourite food. " I think it fair to assume that the bird, Oreoniyza viacclata, finds 

 plenty of the green Carabid. I shot four of these birds (two pairs), each pair 

 widely separated — some miles at least. All of these had [in the alimentary canal] many 

 fragments, thoraces and abdominal segments of one of these green Carabids (either 

 Derobroscus or Brosconymus, probably D. poliius). In no case were elytra present, and 

 I am sure the bird tears them off before swallowing the beetle." Derobroscus micans 

 apparently lives beneath tightly-fitting bark with other more commonplace Carabids. 

 " D. po/itus and Brosconymus live in deep, small cavities in branches of trees or in the 

 pith cavity of some dead branch, and they are naturally extremely difficult to find. 

 I have reason to believe that they largely frequent high branches of tall Koa trees 

 (judging from my extensive observations of Oreoiuyza), and that my captures from 

 the lower branches were merely stragglers. Oreoniyza will go over a Koa tree good 

 for these beetles again and again : a small company (a pair or perhaps as many as 

 eight individuals) is sure to be replaced by another such company many times a day, 

 and thev <2o over every crack and hole of the hig^her branches in the most methodical 

 manner." It is very remarkable that these arboreal forms should be quite flightle.ss. 



Disenockus, p. 200. Some of the species are terrestrial, some arboreal. D. ano- 

 nialus lives under stones ; D. brcvipes, cephalotes, flavitarsis, longipes and fractus are 

 all arboreal, the first four are found only in the moss on the trees, the last in holes. 



Anchonyiiuts, p. 199. I have already recorded that this species forms a "lead" to 

 Derobroscus ; it lives under the bark, or in the holes, of trees. 



Chalcomemis, p. 206. These winged forms are all terrestrial. "The Kauai species 



' .Mtliough it would appear probable that Carabidae, so much sought by birds, should be active only at 

 night, the comparatively brilliant colour of these Carabids suggests diurnal habits. 



