contemporaneous situations in Chiapas forests by Hurd, 
Smith and their students, almost all of the modern insects 
caught were small in size. Certainly this is the case in the 
fossil fauna, with 90% of the insects being small to mi- 
nute flies, bees or wasps. The largest insect found thus 
far is an immature cricket, approximately 20 mm. in 
length. Most of the organisms identified to date belong 
to modern genera. Although present investigations indi- 
cate that most of the fossils differ from any hitherto de- 
scribed species, available information on the tropical biota 
is not sufficiently adequate to exclude the possibility that 
at least some species are still living. The habitats repre- 
sented by the insect fauna will not be evident until the 
taxonomic studies approach completion, but this infor- 
mation could potentially contribute significantly to re- 
construction of the amber-producing forests. 
The plant inclusions, excluding pollen and spores, are 
not so common as those of animal origin, particularly 
small insects. The botanical study of this amber is es- 
pecially significant, however, because the deposits occur 
in an area which probably has had tropical vegetation 
since late Mesozoic times. Despite topographic changes, 
some evolution as well as extinction of various elements 
of the vegetation, and some shifting and differentiation 
of vegetational patterns, there is high probability that 
the modern vegetation may provide important clues to 
the nature of the past vegetation and environment. Use 
of information about modern genera that produce resin 
abundantly seems to be particularly feasible. Trees that 
produce copious amounts of resin are not common, and 
it seems probable that, at the generic level at least, many 
of their characteristics would still be identifiable in the 
Oligo-Miocene. These genera are far more abundant in 
the tropics than in temperate regions. Thus, the study 
of the present ecological relationships of resin producers 
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