1908] Habits of Insects as a Factor in Classification 77 



in connection with the plants on which they are feeding will be 

 found to have, both in color and shape, a most perfect protection 

 in connection with the plants on which they are attached. In the 

 little Lonatura there is not only a distinct similarity in the size 

 and color of the small stems of its host plant, but there are short 

 winged forms which fit in at certain seasons of the year still more 

 perfectly with the food plant or the debris on the surface of the 

 ground in which they may be collected. Driatura in the long and 

 short winged forms appears at first sight to be rather conspicuous, 

 but if taken in connection with the places where it lives is found 

 to blend most perfectly with its surroundings and to be thereby 

 very perfectly protected. Perhaps the most striking example 

 among our native species is to be found in the genus Dory- 

 cephalus which lives upon the stems of large grasses, and in this 

 form the head is very much elongated, the wings shortened, and 

 the color so perfectly straw-like that upon the stem of the plant 

 the insect becomes entirely invisible. The males are dark in 

 color with longer wings, and probably rest more continuously 

 on the darker portions of the dried leaves. A still further adapta- 

 tion occurs with the young which collect in the heads of the plant 

 and which resemble most perfectly the glumes of the seeds. So 

 perfect is the adaptation in this form that none of the stages are 

 readily found and it is only by beating the plants that they may 

 be collected. A related species (D. vanduzei) occurring on smal- 

 ler stemmed plants is perhaps even more distinctly specialized, 

 the wings being more reduced and the body more elongate. 



Another case which is especially striking is found in a small 

 capsid which lives at the surface of the ground and which in the 

 female is entirely wingless and the body so modified as to very 

 perfectly resemble an ant. This resemblance does not stop with 

 a superficial similarity, but ma^^ be noticed even in the basal 

 segments of the abdomen which simulate in a striking manner the 

 same segments in the abdomen of the ant. The male of this species 

 is longed winged, very strikingly different from the female, 

 and doubtless lives under quite different conditions, making use 

 of its wings and flying readily from place to place. 



Another quite striking case is to be found in the beach grass- 

 hopper which is common to sand dunes and beaches throughout 

 a quite extended range of the United States. This species shows 

 most perfect adaptation for protection on the surface of the sand, 

 the spots and marking on the body blending so perfectly with the 



