302 FAUNA HAWAIIENSIS 



tenent hairs) and Sinella (with few ocelli and no tenant hairs). The proposal of 

 Schott', supported by Schaffer, that these two groups are not generically separable, thus 

 finds strong support. It is satisfactory that the single specimen of 'this handsome species 

 is better preserved than most of the collection. 



Hab. Kauai, Koholuamano, Perkins, April, 1895. 0"^ specimen only. 



IsoTOMA Bourlet. 

 This large and cosmopolitan genus is easily recognised by the absence of scales, 

 the forwardly directed head, and the appro.ximate equality in length of the third and 

 fourth abdominal segments. The single species in the present collection is of very 

 small size, and presents an unusual assemblage of characters. 



(i) IsotoDia perkinsi, sp. nov. (PI. IX. figs. 17 — 19). 



Length i mm. Antennae \-^ times as long as head; relative length of segments 

 as 3 : 6 : 4 : 5 (fig. 17). Eight ocelli on each side. Each foot with a tenent hair, upper 

 claw evenly curved and toothless, lower claw with a small tooth (fig. 18). Spring 

 evidently borne on the fourth abdominal segment", elongate ; dens three times as long as 

 manubrium ; mucro with evenly curved ventral edge, two rather prominent teeth and a 

 small accessory tooth (fig. 19). Colour apparently purplish-yellow with the antennae 

 dark, the legs and spring pale. 



The single specimen on which this species is founded had unfortunately been 

 allowed to dry up, so that it was impossible to make any detailed examination of the ocelli 

 or to see the post-antennal organ. The peculiarity of the species lies in the evident 

 presence on the fourth abdominal segment of an elongate and slender spring, with a 

 typical mucro. Usually in the genus Isotoma, when the spring occurs in this position 

 (instead of apparently on the fifth segment) it is short with a stout and blunt mucro. 



Hab. Kauai, Koholuamano, Perkins, April, 1895. One specimen. 



Earn. ACHORUTIDAE. 



Neanuka MacGillivray. 



Anoiira Gervais, Suites a Buffon, Insectes Apteres, 1844 (nom. praeocc). 



The insects of this genus are characterised by the tuberculate appearance of the 



body, the conical projecting mouth, the absence of a lower claw to the foot, of anal spines 



and of pseudocelli ; also by the presence ot a peculiar sense-organ at the tip of the fourth 



antennal segment. Ocelli and a post-antennal organ are usually present. Several 



species of the genus have now been described from various parts of the world. That 



' Proc. Calif. Acad. Sciences (2), vol. vi. 1896, p. 180. 



- Willem has shown (Me'm. Cour. Acad. Roy. Sciences Belgique, Lvui. 1900) that the spring of the 

 Collembola always belongs to the fourth abdominal segment, though in most forms it looks as if inserted on 

 the fifth. 



