132 Cockroaches, Locusts, Grasshoppers, and Crickets 



along in its solemn way, holding up its two fore legs as in the act of devo- 

 tion, desired it to sing the praise of God, whereupon the insect carolled 

 forth a fine canticle! 



More amazing than the Mantids for modification of form and appear- 

 ance away from the usual insect type are the members of the family Phas- 

 midae. The only representatives of this family in the United States are 

 the walking-sticks, or twig insects (Fig. 164), of which half a dozen genera, 

 with from one to three species each, have been recorded. The only one 

 of these genera which is found in the East is Diapheromera, of which D. 

 jemorata is the common species. Our other Phasmids are found in the 

 West or extreme South. All of our species are wingless and are generally 

 sluggish in movement, and depend for protection largely on their amazingly 

 faithful resemblance in shape and color to twigs, and on their capacity to 

 emit an ill-smelling fluid from certain glands on their prothorax. Diaphero- 

 mera femorata (Fig. 164) feeds on the leaves of oaks, walnuts, and probably 

 other trees. It drops its hundred seed-like eggs loosely and singly on the 

 ground, where they lie through the winter, hatching irregularly through 

 the following summer. Some may even go over a second winter before 

 hatching. Femorata may be either brown or green; so it frequents dead 

 or leafless, or live and green-leaved parts, according to the correspondence 

 of its body color with the one or the other of these environments. The long, 

 slender, wingless body, the thin, long legs held angularly, and the harmonizing 

 body color, all serve to make the walking-stick well-nigh indistinguishable 

 when at rest on the twigs. 



In tropic and subtropic countries the Phasmids are numerous (over 600 

 species are known) and present other striking resemblances to the details 

 of their habitual environment. A conspicuous and perfect example of 

 resemblance is the green leaf-insect Phyllium (PL XIII, Fig. 2), whose wings, 

 flattened body, and expanded plate-like legs, head, and prothorax, all bright 

 green and flecked irregularly with small yellowish spots, like those made 

 by the attacks of fungi on live leaves, combine to simulate with wonderful 

 effect a green leaf. 



Other examples of such protective resemblance and a discussion of the 

 origin and significance of the phenomenon may be found in Chapter XVII 

 of this book. 



The genera of Phasmidae occurring in the United States may be distin- 

 guished by the following key: 



Tibiae with a groove at tip to receive the base of the tarsi when bent upon them. 

 Antennas with less than twenty segments, and much shorter than the fore femora. 



BACILLUS. 



