NO. 7 PROTECTIVE ADAPTATIONS McATEE 35 



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 shield- 

 ing 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 thougli highly protective in character, 

 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 witli its background of lichened pine bark, the Red-legged 

 and the Two-striped Locusts among the yellowish green of herbage, and other 

 species of Melanoplus, — M. mancus, M. fasciafus, etc.,- — whose darker tints 

 resemble those of fallen leaves from the Vaccinium thickets amid which they 

 live. 



One who has not watched these creatures out of doors can appreciate to 

 but a slight degree the effectiveness of sympathetic coloring as a means of 

 concealment. Let him but try to pick out from its background immoliile grass- 

 green Cone-head, leaf-browu Shield-backed Grasshopper, or any of the Locusts 

 just mentioned, and he will realize as never before the importance to the 

 defenceless insect of Alother Nature's protective mantle of invisibility. 



The wing-covers of certain katydids and allied forms are very 

 leaflike, the resemblance being carried so far in certain cases, it is 

 said, that the spots like those due to fungi and the tracks of leaf- 

 mining insects are closely imitated. 



The leaping powers of the Saltatoria, remarkably developed in some 

 forms, must be classed as defensive ; most of these insects have 

 powerful mandibles also, a few of them indeed being markedly 

 carnivorous. 



Locusts of the subfamily Oedipodinae, especially, have another 

 adaptation some consider protective. For instance E. B. Poulton 

 says: ' " The brightly coloured hind wings of many moths {Catocala, 

 Tryphacna, etc.) and grasshoppers {Oedipoda, etc.) which flash out 

 conspicuously when the insect becomes active, and disappear equally 

 suddenly when it alights, probably serve, as Lord Walshingham has 

 suggested [Proc. Ent. Soc. Lond. 1890, pp. ITiii], to confuse a 

 pursuing enemy." It may be noted that Morse considers these colors 

 as recognition markings. 



Finally, among protective adaptations, certain Orthoptera are said 

 to mimic other insects, as for instance Membracidae, Phasmidae, ants, 



' Essays on evolution, p. 303, 1908. 



