2-1 



observed in some numbers in some cane-fields and certainly breed- 

 ing there. 



I have frequently observed these flies in the forests of several 

 islands where leaf-hoppers are abundant, but never in the long 

 course of my collecting have T previously found them in the cane- 

 fields or outside the forest. As it is knoAvn that insects of this 

 group are parasitic on leaf-hoppers, it is highly probable that 

 the species observed by me in fields attacked by the cane-leaf- 

 hopper are parasitic on this species. This species of PipHiiculus 

 appears to be undescribed, though very close to the P. iiigrofarsa- 

 tiis, collected by me in the Kona forests. 



(m) Sl'idcrs of Many Species. 



Tn my early reports I called attention to tlie large number of 

 spiders generally found in the cane-fields, and there is no doubt 

 tliat owing to the abundance of food furnished b)- the leaf-hoppers 

 these have in some localities multiplied to an extraordinary degree. 

 Fully twenty species of diverse families are knowai to me to fre- 

 quent the cane-fields, a large proportion of these being imported 

 species. The species most numerous on one plantation are often 

 extremely dififerent from those on another. Thus in one locality 

 it is a common Tctragnatha, in another a species of Cyclosa or 

 Argiope, in another an Attid or Thomisid, that most abounds; in 

 general two or three forms are abundant on a single plantation. 

 I believe the species that hunt their prey without the use of webs 

 are far more effective against leaf-hoppers than those that spin 

 these. To' what extent the multiplication of individuals has pro- 

 ceeded in parts of some plantations may be judged from the fact 

 that as many as 50 nests of one single species of spider have been 

 counted on a single leaf., and each of these nests will probably con- 

 tain from 40 to 50 eggs on an average. 



(mm) Parasite of Spiders. 



Some of the most eft'cctive species of spiders are themselves not 

 exempt from attack. Thus a Cryptic Ichneumon pierces the cov- 



