i 82 
FJSCICVLI MALATENSES 
10. Collyris sarawakensis, Thoms. 
Bukit Besar, Nawngchik. 2,500 feet. May, August, September, 1901. 
This species and the preceding, which it closely resembles, were not 
uncommon on Bukit Besar. They frequented fairly open paths where there 
was much alternation of light and shade, and were extremely active and restless 
in their movements, settling for a few seconds on some projecting twig or leaf 
and then flying off with great rapidity. While on the wing they could with 
difficulty be distinguished from the smaller wasps of the family Scoliidae and 
from certain Diptera {Sciomyzidae .^), but this resemblance quite vanished when 
the beetles were at rest. Perhaps, however, the most interesting member of 
this mimetic association is a Hetsromerous beetle, originally described by 
Westwood as Styrax tricondyloides, and which appears to be exceedingly rare, 
as there is only a single specimen in the Bates collection at the British Museum. 
The single specimen that we captured, which we did not specially note at the 
time, was secured on Bukit Besar in the sweep net on April 20th, and so close 
was its resemblance to the three preceding species that it was actually taken 
down to the British Museum with the Cicendelids, and only recognized then 
on a rigid examination as not belonging to this family. Both it and its models 
have red legs and cyaneous elytra, which are strongly rugose at their anterior 
halves, while the posterior portion is smooth and shining, though in the case 
of S, tricondy hides it is slightly striated. The thorax of the mimic has two 
large tubercles on the disc, projecting slightly forwards as a kind of hump, 
with the result that the thorax appears to be slightly constricted anteriorly, as 
is the case in the species of Collyris. 
It is not at first sight easy to understand why this section of the 
Cicendelids should be so very extensively mimicked' as they certainly are in 
the Eastern tropics. They are of course highly raptorial insects, but I am not 
aware that it has ever been shown that they are nauseous, while even if this 
was the case they are not, at any rate in the Malay Peninsula, sufficiently 
abundant for any protective qualities that they may possess to prove any 
advantage to their mimics. Possibly all cases in this group may ultimately be 
shown to be instances of Mullerian rather than Batesian mimicry, though the 
extreme rarity of the mimic is an argument against this supposition. 
11 . Collyris crassicornis, Dej. 
Mabek, Jalor. 23rd July, 1901. 
‘ Running on leaves of shrub, and flying rapidly from shrub to shrub.’ 
I. Cf. R. Shelford, Troc. Zool. Soc. 1902 (2), pp. 233-234, pi. xix, figs. 1-6. 
