METAZOA INSECTA. 415 



and the walking-stick have acquired unique specializa- 

 tions. The prothorax of the adult Stagmomantis Carolina 

 Linn., (Nos. 1012, 1013), is a long, slender segment, on 

 the forward end of which are borne the extremely large 

 fore legs that are adapted even in the larval state for 

 seizing living prey, and which are usually raised in read- 

 iness to act whenever occasion offers. The other two 

 pairs of legs are locomotor organs and are slightly 

 modified. The wings of Mantis are too small to be of 

 use, and the motions of this walking type are extremely 

 slow. 



Certain species of Mantis and also of the walking-stick 

 (No. 1014, Cythocrania gigas) have remarkable plant-like 

 features in the form of leaf-like wings, but in the single 

 species found in New England, Diapheromera femorata 

 Say (No. 1015), the wings have wholly disappeared. 



These insects are among the good illustrations of what 

 is known as protective coloration. In the spring time 

 their color is a vivid green, but as autumn approaches 

 they take on brownish tints. Whatever may be the cause 

 of these changes, whether due to conscious or uncon- 

 scious adaptation of the insect to its environment, to the 

 direct effects of heat and cold, to the age of the animal, 

 or to some unknown cause, they certainly render the 

 insect less conspicuous and in this way serve to protect 

 it against its enemies. One of the most remarkable cases 

 of this kind is seen in the genus Phyllium (No. 1016, 

 P. scythe}. The anterior wings of the female resemble 

 leaves and their hues change with the changing seasons. 



Among the more specialized Orthoptera are the Acridi- 

 idae or locusts, the Locustidae or grasshoppers, and the 

 Gryllidae or crickets. 



The Acridiidae are good type forms not only of the 

 Orthoptera but of the class Insecta. The larva (No. 

 1017 ; PI. 1018, fig. i) possesses the similar thoracic 

 and abdominal segments that are comparable with those 

 of the Thysanura. The mouth parts are the same in 



