414 



with the possible exception of loysanensis and semlfJavus, of 

 whose habits we know the least at present. Not only do the 

 different species have the same host but more remarkable still 

 is the fact that two of these closely allied species have been 

 found together, semilideus and hridwelll thus occurring within 

 a few rods of each other on the south wall of Palolo Valley. 

 The effect of isolation, however, is shown in these species to 

 a fine degree. 



The introduced species, fuUaiuayi, belongs to Xanthoen- 

 vyrtus, setisu stricto, whereas apterus and allies fall in the 

 subgenus, Mirastymachus Girault, which differs chiefly in hav- 

 ing three club joints instead of two. With only a few species 

 of the two groups known outside of Hawaii (there being one 

 European, two American and three Australian species de- 

 scribed) the value of this character is not fully established, 

 although it may be found necessary to recognize Mirastymachus 

 as a good genus later. The main distinguishing character, 

 moreover, obtains only in the female sex. 



The following descriptions have been made comparative 

 only, on account of the close similarity of the species to 

 apterus, to the full description of which reference should be 

 made*. The depression on the dorsal surface of the head be- 

 tween the eyes noted in the previous paper proves to be due 

 to shrinkage, as this space is slightly convex in living or fresh 

 iiuitevial. Since the head in each s])ecies shrinks a little 

 differently from other species and somewhat imiformly this 

 character may have some value, although it is by uo means 

 absolute. Occasionally a specimen of large size will ])o found 

 which remains unshrunken as is the case in the type of 

 soniflaru-s and in one specimen of apfcriis from Kahihi, 

 Oahu. 



The f(^llowing synoptic tables to the endemic species have 

 been prepared to show their relationshi]) to each other and 

 ■ to facilitate their identification. 



*Proc. Haw. Entom. Soc, vol. 4, No. i, p. 20T 



