ABT. 21. NORTH AMERICAN SAWFLY LARVAE MIDDLETON. 27 



popleurite triangular, of heavy chitin and sparsely haired ; posthy- 

 popleurite large and sparsely haired ; legs with 4 joints and an apical 

 claw, joint 3 with small soft pad on inner side at apex. Abdomen : 

 The tergum of urites 1-9, inclusive, is composed of areas A, B, C. 

 and D (C inclined to subdivide into C^-^), B and C^ are sparsely 

 haired and A and D are bare; urite 10 consists tergally of an epi- 

 proct, which is sparsely haired and without pseudocerci; urites 1-8, 

 inclusive, with spiracle in spiracular area and urites 9 and 10 with 

 spiracle wanting and the spiracular area not demarked; urites 1-8, 

 inclusive, with the alar area distinct, bilobed, and sparsely haired, 

 urite 9 the alar area smaller but distinct and haired and urite 10 

 with the alar area wanting ; pleurum ; urites 1-7, inclusive, with pre- 

 epipleurite distinct and separate from postepipleurite, and both 

 sparsely haired, urite 8 with preepipleurite indistinctly separated 

 from postepipleurite and both sparsely haired, urite 9 with pre- 

 epipleurite indistinguishably united with postepipleurite and form- 

 ing a sparsely haired epipleurite and urite 10 with epipleurite not 

 recognizable; urites 2-7, inclusive, with hypopleurite distinct and 

 not divided into prehypopleurite and posthypopleurite and urites 

 1, 8, 9, and 10 with hypopleurite indistinct or wanting; urites 2-7, 

 inclusive, with well-developed uropods, urites 1, 8, and 9 with uro- 

 pods wanting and urite 10 with postpedes and postcallus of moderate 

 size. 



Color. — Head: Almost entirely dark brown; eye disks black. 

 Thorax : White, except for gray spots about base of hairs on B and 

 C of the prothorax, A, B, and C of the mesothorax and metathorax 

 and preepipleurite and posthypopleurite of entire thorax, and the 

 dark brown chitin of prehypopleurite, leg joints, and claw of entire 

 thorax. Abdomen: White, with the spiracles gray and with faint 

 gray spots about base of hairs on folds B and C, the alar area and 

 preepipleurite and postepipleurite where separate and epipleurite 

 where preepipleurite and postepipleurite are not separated, on urites 

 1-9, inclusive, and with very faint indistinct grayish markings on 

 the epiproct of urite 10. 



Prepupa. — (One that had not spun its cocoon and contracted.) 



Size. — 10 mm. in length. Head : 1 mm. high by 1 mm. wide. 



Structure. — Similar to sixth stage of larva. 



Color.— Head : Whitish ; faintly gray in front ; eyes and eye disks 

 black; mandibles black. Thorax: Legs pale, otherwise similar to 

 sixth larval stage with markings somewhat darker. Abdomen: 

 Similar to sixth larval stage but with darker markings. 



Cocoon.—^ mm. long by 2 mm. broad, capsule-shaped; brown in 

 color ; consists of single case, thin but finely or closely woven. The 



