5(5 [March, 



NOTES ox OLIGOTOMA INSULARIS, McLach. {EMBIIDM), AND ITS 

 IMMATURE CONDITIONS. 



BY E. C. L. PERKINS, B. A. 



This interesting species is found throughout the Hawaiian group, 

 but not at high altitudes, 2000 feet above sea level being probably 

 about the limit of its range. The places frequented by it are very 

 various : in the mountains it is generally found in the interior of dead 

 branches ; lower down, on or under the bark of trees ; and on the 

 dry and barren lowlands of the lee side of the islands, beneath the 

 rocks which strew the ground. 



In any case the insects spin webs resembling those of spiders, 

 consisting of simple tubes, others more diffuse containing tubes, and 

 sometimes simple masses of web. In these tubes they live, at least by 

 day, but the winged males fly rather freely at night, and are readily 

 attracted by the lights in houses. On the dry rocky ground the}' are 

 sometimes the most abundant element of the scanty fauna, one or more 

 being found under nearly every stone. Even as many as a score of very 

 minute individuals will inhabit a single mass of web ; of adults three 

 or four under one rock is a common number, or about a dozen adults 

 and younger individuals mixed. Under rocks I have found the num- 

 ber of adult females to far exceed that of the males, which may have 

 been partly due to season, or to the activity of the latter, which fly 

 away on acquiring their wings. Sometimes the female will run off 

 with great speed when disturbed like the most active earwigs ; pro- 

 bably such individuals have, at the time when they are exposed, strayed 

 from their webs, for, as a rule, they keep hidden in these until they 

 are dx'iven out. Within their tubes they run with ease and quickness 

 backwards or forwards ; when exposed they prefer to run backwards, 

 and the speed with which they do so is quite remarkable. 



The first trace of wing formation that I could detect was in an 

 individual not greatly inferior in size to the adult male. This begins 

 as a slight modification of those lateral portions of the meso- and 

 metanota which are curved downwards, but apparently includes also a 

 portion of their true dorsal surface. The boundaries are defined by 

 the slight difference in colour of the parts which form the rudiments 

 of the wings, for these parts are lighter in colour than the rest of the ' 

 nofa, though of the same chitiuous texture. They are also delineated 

 by very faintly impressed lines, extremely difficult to see except in 

 very favourable position and light. Already the inferior lateral 

 margins of the nota appear to be slightly raised or reflexed, and the 

 apices of the wing rudiments project slightly beyond the posterior 



