no. 2083. LARVAE OF GENUS DIMORPHOPTERYX—MIDDLETON. 499 



eyes brown; top black capped; mandibles brown; thoracic protuber- 

 ances present, mesothoracic one slightly smaller than prothoracic 

 pair; dull golden yellowish green, alimentary canal colored dark 

 olive green; subdorsal anal spines black tipped. 



Stage II. — Length, 5.5 mm.; prothoracic width, 1 mm.; head, 1 

 mm. high by 0.67 mm. broad; general appearance same as first stage. 



Stage III. — Length, 8 mm.; prothoracic width, 1.25 mm.; head, 

 1.33 mm. high by 0.875 mm. broad; general appearance the same. 



Stage IV. — Length, 9.5 mm.; prothoracic width, 1.5 mm.; head, 

 1.67 mm. high by 1.13 mm. broad; general appearance the same. 



Stage V. — Length, 10.5 mm.; prothoracic width, 1.75 mm.; head, 

 2 mm. high by 1.5 mm. broad; general appearance the same. 



Stage VI. — Length, 15 mm.; prothoracic width, 2.33 mm.; head, 

 2.5 mm. high by 2 mm. broad, otherwise the same; prothoracic 

 protuberances large and prominent, twice as high as thick; mesotho- 



Fig. 2. — Anterior aspect op Fig. 3. — Anterior aspect of 



head of dlmorphopteryx head of dlmorphopteryx 



castaneae. autumnalis. 



racic protuberance slightly smaller; pleural region and anal plate 

 bright (not shiny) yellow; dorsum (alimentary canal) dark green and 

 separated from yellowish pleural region by blackish lateral lines run- 

 ning posteriorly from base of each yellowish prothoracic protuber- 

 ance, to and including the large pair of white-tipped subanal pro- 

 tuberances, where they meet in a transverse band; anal spines black. 



Stage VII. — (Prepupa). Length, 11.5 mm.; prothoracic width, 2.5 

 mm.; head, 2 mm. high by 2 mm. broad, dark above, not black, 

 pale below antennae and about mouth, antennae dark, mandibles 

 brownish; armature of anal plate reduced to tubercles, subdorsal pair 

 as widely separated as in sixth stage, but united basally with the 

 nearest lateral tubercle; skin yellow; spiracles slightly darkened 

 in undarkened pleural band. 



Remarks. — The larvae of this sawfly, in the first three stages, feed 

 upon the upper epidermis and parenchyma of the chestnut leaves, 

 but from the fourth to the sixth they characterize their work by 



