242 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
The majority of the colors exhibited by Orthoptera are pig- 
mentary in character. They He in the outer (cuticula) or inner 
(hypodermis) layer of the integument, or in both, and affect 
each other. The development of the pigment depends in part 
on exposure to light and oxygen, as shown by the gradual darken- 
ing of a newly molted insect. Sometimes the cells of the hypo- 
dermis contain colored granules or oil drops which give red, white, 
or yellow effects from the exterior; sometimes they contain 
diffused chlorophyll (green) or xanthophyll (yellow) pigment 
derived from the food plant. Some pigments are known to be 
excretory products. 
Colors which resemble the usual background are said to be 
sympathetic; others, non-sympathetic. Good examples of 
sympathetic coloration are shown by the green and the brown 
phases of the Bicolored Locust (Dichromorpha viridis) and Green- 
striped Locust (Chortophaga viridifasciata) , the green resembling 
the hue of living, the brown that of dead vegetation of the fields 
in which they live and against which they are seen. In the 
Salt-marsh Locust (Orphulella olivacea) an olive tint is devel- 
oped in both phases harmonizing with that of the salt-marsh 
vegetation. 
The Orthoptera as a whole have received less investigation as 
regards color than some of the more brilliantly clad insects, and 
only certain elementary and general statements can be made 
regarding them. The usual brown or black hue of Earwigs, 
Roaches, terrestrial Crickets, and Cave-crickets probably has no 
especial biological significance. It is a color generally developed 
in chitin (the chief element of the body-wall) after exposure to 
light and air. In habits these Orthoptera are typically nocturnal 
and live in burrows, crevices, or cavities; these colors suit the 
circumstances well and are protective to a considerable degree, 
but probably should not be classed as purely sympathetic. 
The coloration of Walking-sticks, Tree-crickets, Katydids, 
Cone-heads, and Meadows-grasshoppers is obviously sympa- 
thetic and protective. They are exposed during the day when 
their foes are most active, and their coloring protects them from 
observation among the green leaves or the gray and brown twigs 
of their haunts. Probably that of the Shield-backed Grass- 
hoppers (Atlanticus) also, though differing widely, should be 
