BIOLOGY OF SATURNIID MOTHS—BLEST 451 
Barro Colorado Island lies in Gatun Lake. Consisting of some 
13 square miles of seasonal tropical evergreen forest, it was estab- 
lished artificially when the surrounding area of lower land was 
flooded during the construction of the Panama Canal. The forest 
is intersected by trails, which are maintained by the staff of the re- 
search station, covering the whole island save for the clearing in 
which the living accommodation and laboratories are placed. The 
forest itself is not, as has sometimes been stated, virgin, for areas of 
it were under cultivation before it was taken over as a biological 
reserve in 1923. While for the botanist, therefore, the basic ecologi- 
cal status of much of the forest may appear questionable, for the 
zoologist, and especially for the invertebrate zoologist, the whole 
area is uniquely suitable for the investigation of tropical biology. 
To date the greater part of the intensive work carried out on the 
island since its inception has been faunistic; thus the necessary founda- 
tion for ecological research has been laid to a degree which probably 
no other New World tropical area can equal. Even so, discoveries 
can still be made even in the best-worked groups. The arachnids 
are among the best known of the island’s invertebrates, thanks to 
the redoubtable efforts of Prof. A. M. Chickering: nevertheless I 
found three specimens of a ricinuleid near to Cryptocellus emargi- 
natus Kiwing living under stones in deep litter on the forest floor. 
While the order has been found, mostly as single specimens, in 
Honduras, Costa Rica, Nicaragua, and Colombia, this is the first 
record for Panama. 
For the biologist who has been accustomed to the undemanding 
conditions of temperate woodlands, the inaccessibilty of the greater 
part of the tropical fauna is disconcerting. Much of the copious in- 
sect life is confined to the forest canopy some 90 feet or more above 
the forest floor. There is an abundance of different species even 
within restricted taxonomic groups, and this prolific speciation is one 
of the most important and still imperfectly understood features of 
tropical zoology. In the course of a 6-month period, some 35 species 
of saturniid moths were attracted to lights placed in the laboratory 
clearing, and this tally by no means exhausted the known fauna of 
the area. Many of the species were common. Yet the picture yielded 
by attempts to search for the larvae was a very different one. Those 
of only one species, Lonomia cynira, were found commonly, and this 
because of their habit of resting in smal] groups on the trunks of 
slender second-growth trees, at a height of some 2 to 4 feet above the 
ground. Very occasionally the larvae of some six other species were 
encountered, generally as fully grown individuals in their last instar, 
when the initially gregarious caterpillars have scattered and are living 
singly on their food plants. Yet this meager harvest was the result 
of several weeks of quite frequent searching. Most of the larvae of 
