1925] Mystery of “ Trilobite Larvae” Definitely Solved 135 
short and cylindrical; third much broader than long, tapering 
toward the base, fourth to sixth about one and one-half times 
longer than broad; slightly emarginate at the apex, seventh to 
tenth gradually becoming longer and more slender, apical joint 
the longest, being fully four times longer than broad, at the 
apex rounded. Frons vertical, labrum thin, membranaceous, 
tapering anteriorly, slightly emarginate in front and here trans- 
parent; mandibles very strongly developed, perhaps serving 
some purpose in copulation, maxillae and labium of the normal 
type; sides of head behind the eyes strongly converging back- 
wards. Prothorax more than twice broader than long, nearly 
semicircular, disc with a slight transverse basal impression, 
shining, hind margin emarginate, hind angles slightly protruding, 
obtuse; scutellum fairly big, triangular, rounded at the tip. 
Elytra showing a tendency to develop faint longitudinal costae, 
widened towards the tips, posteriorly rounded; tibiae long and 
slender; claws with a small tooth-like dilatation at the base. 
Abdomen narrow, the first seven segments fairly equal in size, 
hairy. Measurements: Total length 7 mm. greatest width 2.7 
mm. 
Habits: Nocturnal. 
Locality. Mt. Batu Gading near Lundu, altitude 1500-3000 
feet, Sarawak. Probably distributed over a wide area. Its $ 
larvae found by me (1 spec.) near Lio Matu on the Baram River 
and on Mt. Dulit on the Tinjar River, North Sarawak, altitude 
2000-4000 feet. 
$ (Plate III fig. 2a) : Of very large size, in general shape and 
appearance like the female-larva, but yellowish-white. 
Measurements: Slight^ smaller than the full grown larva, 
ranging from 65-75 min. 
Adult-Larva 
9 : Body black, except a small median patch at the post- 
erior margin of all thoracic and the first eight tergites, which is 
yellowish; abdominal processes and lateral margin of thoracic 
segments whitish; the whole upper surface finely shagreened 
and punctured. Head small, completely retractile within the 
prothorax; antennae retractile, two-jointed, terminal joint hairy, 
