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others obtained from collecting skins when adults were emerging. In 
previous studies (Young 1972; 1975a; 1980a, b; 1981a, c) I have 
illustrated and discussed distinguishing features of cicada nymphal 
skins. Based upon these materials, a key to the Costa Rican cicada 
fauna, using both adults and nymphal skins, is being formulated 
(T.E. Moore and A.M. Young, in preparation). In the present study, 
it was very easy to distinguish nymphal skins of Fidicina species 
(three species) on clear-cut differences in color pattern and size; the 
Zammara species studied has nymphal skins very different in color 
and body profile from the others (see also Young 1972), while the 
two species of Carineta species had nymphal skins differing in color, 
even though of very similar size. One species has a very dark brown 
nymphal skin, and the other, light brown. Based upon matching of 
skins with adults done by myself and T.E. Moore, I am reasonably 
certain that matches of field collections of skins with adults is very 
reliable. Voucher specimens of fruits and leaves of the trees having 
nymphal skins beneath them were collected and sent to specialists 
for determination. 
Other observations included determining the places on the ravine 
where adult cicadas were heard chorusing as a means of estimating 
preferences among species for the river-edge area and top of the 
ravine. In some instances, diurnal patterns of calling were also noted 
and the trees used for calling. Once the species were determined, 
records of captures of cicadas in other regions of Costa Rica were 
checked by examining the University of Michigan collections and 
data bank on Neotropical species in other museums, as a means of 
determining if the Cuesta Angel species were found elsewhere in 
Costa Rica. Because virtually nothing is known about the geo 
graphical distributions and habits of Neotropical cicadas in general, 
vouchers of both adults and nymphal skins were saved and placed in 
collections at the University of Michigan and the Milwaukee Public 
Museum. 
Owing to the steep terrain and heavy rains of the region, a small 
experiment was conducted on estimating the rate of disintegration 
of cicada nymphal skins on both forested slope and river-edge 
forest. Such a test would tell me how many skins were being missed 
between census intervals because they were possibly disintegrated, 
particularly on the slopes, before the next census was taken. Thus in 
the May 1973 census, two groups of fresh skins of one of the larger 
species, each group containing ten skins, were established, one 
