THE CANADIAN ENTOMOLOGIST. 189 



thoracic segments, wing-pads and legs being slightly dark in colour. 

 This darkness deepens with the age of the pupa. Length 3.4mm.; 

 width at base of wing pads, 1.2 mm. 



The head lies incurved under the prothorax, the developing 

 mouth-parts showing very distinctly. The eyes are small and 

 almost black. The antenna? lie in front of the eyes and extend 

 under the pronotum, thus being concealed from the dorsal view. 

 The wing-pads are prominent. 



The pronotum is large and rather densely covered with fine 

 colourless setae. The outer angles of the anterior margin each bear 

 a long, curving spine, measuring .32 mm. The posterior outer 

 angles also, each bear a spine measuring .28 mm. These spines 

 are yellowish brown in colour. They support the pupa in its 

 chamber, preventing it from coming in contact with the coarse 

 grains of sand. 



The abdomen is composed of nine segments, the posterior 

 margins on the dorsal side being strongly elevated into narrow 

 ridges. These ridges are clothed with numerous short setae. The 

 ninth segment bears on its dorsal" side two curving stout cerci, 

 measuring .4 mm. in length. These cerci almost completely 

 conceal the segment from which they arise. The pupa rests on 

 its back in the pupal chamber. By the aid of the prothoracic 

 spines and cerci together with the numerous short setae arising 

 from the raised ridges of the abdomen, injury from the roughened 

 walls of the pupal chamber is avoided. The posterior margins of 

 the wing pads and the legs are also provided with many short setae. 



THE KNOWN NYMPHS OF THE CANADIAN SPECIES OF 



LESTES (ODONATA). 



BY E. M. WALKER, TORONTO. 



The only attempt that has yet been made to separate the 

 nymphs of the North American species of Lestes is that of Pro- 

 fessor J. G. Needham in his report on "Aquatic Insects in New 

 York State."* Professor Needham gives an excellent generic descrip- 

 tion of the nymph and a table for the partial separation of the five 

 species that he reared, viz.. L. uncatus, unguiculatus , rectangularis, 

 forcipatus, and enrinus. Good figure s are given of L. rectangularis. 



♦Bull. 68, N.Y. State Museum, 1903, pp. 22S-236. 

 June, 1914 



