166 A NATURALIST IN BORNEO 



shaped structures of only two joints ; a well-defined 

 crescentic area of the cuticle at the tip of the second 

 joint is very thin, and as the body of the antenna is 

 occupied by many nerve-fibres and large ganglia, 

 these organs must be very sensitive. The larvae 

 crawl about with a looping movement something like 

 Geometer caterpillars, and they constantly apply the 

 tips of their minute antennae to the surface on which 

 they crawl. As their only visual organs are a pair of 

 small ocelli, so simple in structure that it is impossible 

 to imagine them capable of more than appreciating 

 the difference between light and darkness, the antennae 

 are undoubtedly the most important sense organs that 

 the creatures possess. 



The larvae feed either on Mollusca or else on such 

 small soft-bodied creatures as Scolopendrella, Thysanura, 

 and perhaps Dipterous larvae, it is not certain which, 

 for I was never able to find out exactly what they 

 ate, though I was successful in rearing them when 

 kept in decaying wood. 1 It is certain that the larvae 

 do feed on animal matter, for their mouth-organs are 

 constructed on the same plan as those of the Glow- 

 Worm, which, as is well known, devours snails. A 

 more or less detailed account of the mouth-parts in 

 Lycostomus larvae will illustrate how admirably these 

 organs are adapted for sucking the juices of the 

 creatures on which they prey. 



The mandibles are fine sickle-like blades, each 

 enclosed in a delicate sheath, and perforated through- 

 out their length by a delicate canal into which open 



1 Dr. D. Sharp, F.R.S., who has bred the English Lycid, Eros 

 aurora, from the larva, tells me that he has never really discovered 

 what the larva feeds upon. 



