298 

 New Hawaiian Delphacidae. 



BY r. ISLUIK. 



(Eead December 14, 1916.*) 



Dnriiio- the last twelve months considerable additions have 

 been made to onr Delphacid collections, several new species 

 have been captnred and our knowledge of the food-plants of 

 many species has been corrected or extended. This lias been 

 chiefly dnc to the energy of Messrs. P. H. Timberlake, O. H. 

 Swezey and AV. M. Giffard. Mr. Giffard has also procured 

 a small but interesting collection from the Island of Lanai. 

 This collection Avas made by Mr. G. C. Mnnro witl\ the assist- 

 ance of 11. Gibson and it brings the number of species known 

 from that island u]) to fifteen, and places it third on the list. 

 This indicates that the nund)er of s]>ecies still unknown from 

 the three lai-ger islands of Kauai, ^Molokai and ^laui is very 

 great. 



The new species sh(nv the same degree of phallic differen- 

 tiation as do s])eeies previously described, in some cases they 

 are closely i-eliited to known forms but in others they appear to 

 be quite isolated. The Hawaiian species of Kcllsia have been 

 considered as foi-eign ; the four s])ecies belong to three distinct 

 ty]i('s which, without intermediate forms, cannot he conceived 

 as having any relationshi)). Two species, A", sporoholicola and 

 A', stiu'zciji. are closely related, and it is probable that one is 

 of local origin. f. Elsewhereij: 1 have ])ut ftu-ward the sugges- 

 tion that this ]ihallic differentiation represents a differentiation 

 of the germ-plasm and, although T have given the subject con- 

 siderable thought, I can offer no better reason. I believe that 

 one of the first steps in species formation among Hawaiian 

 Delphacidae is a change of food-])lant. In nuniy cases this 

 will lead to isolation and may eventually lead to differentiation 

 of the germ-plasm. Mr. W. M. Giffard brought to my notice 

 the fact that certain s])ecies feeding u])on more tlian one food- 



* The captures, etc., have been brought up to date (February, 1917). 

 t Since this was written, A'. p<ilu<hitii Kirk, has been found to have 

 a wide range in the Pacific. 



i Pro. Haw. Ent. Soc. Ill, 1916, p. 210. 

 Proc. Haw. Ent. Soc. Ill, No. 4, May, 1917. 



