244 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
The coloration of the second class of surfaces (dorsal, lateral, 
etc.) is, with few exceptions, highly sympathetic in character, 
harmonizing with or resembling very closely, often to a marvelous 
degree, the background of the insect's environment. Earth 
tints, rock and sand textures, the infinitely varied browns, greens, 
and grays of living and dead vegetation, yellow, orange, rose, and 
silvery white are all represented in spots and streaks, the effect 
being to merge the insect indistinguishably into its background 
while at rest, thus shielding it in a very high degree from the 
observation of its foes. These colors are of great protective 
value at the present time, natural selection continually acting to 
preserve and perfect them, but though highly protective in char- 
acter, they are without doubt primarily due to physiological 
processes and influences as yet imperfectly understood. 
This type of coloration is admirably illustrated among New 
England species by the Seaside Locust and Sand Locust which 
live on sandy backgrounds, the Snapping and the Ledge-loving 
Locusts on rock habitats, the Coral-winged and^the Clear-winged 
Locusts in fields; and in the plant-perching species the Pine- 
tree Locust with its background of lichened pine bark, the Red- 
legged and the Two-striped Locusts among the j^ellowish green 
of herbage, and other species of Melanoplus,—M. niancus, M. 
fasciatus, etc., — whose darker tints resemble those of fallen leaves 
from the Vaccinium thickets amid which they five. 
One who has not watched these creatures out of doors can 
appreciate to but a shght degree the effectiveness of sympathetic 
coloring as a means of concealment. Let him but try to pick out 
from its background immobile grass-green Cone-head, leaf- 
brown Shield-backed Grasshopper, or any of the Locusts just 
mentioned, and he will realize as never before the importance to 
the defenceless insect of Mother Nature's protective mantle of 
invisibility. 
The colors of the third class of surfaces (parts exposed occasion- 
ally), are on the contrary, in many cases non-sympathetic in 
character to a high degree; they are often bright and stronglj^ 
contrasted, striking in effect and at times exceedingly conspic- 
uous. This is very generally the case among the North American 
Oedipodinae and certain Locustinae (Acridinae), and is well 
illustrated among our New England Locusts by the species of 
