342 THE CANADIAN ENTOMOLOGIST. 



Honey-yellow and black ; on Betula Crcesus latitarsus. 



Honey-brown and leaden-black; on Corylus and h\i\y\%.Neinatus coryli-' 



42. Green with black spots ; on Populiis . . . . Nematiis Hudsonii-viagnus. 

 All black ; on Salix Nematiis ventralis. 



43. The tubercles minute dorsally 44 



The tubercles of nearly equal size ; body blue green ; on 



Ribes Nematus ribesii. 



44. " Black spotted " Nematus pallidiventris^ 



A row of subdorsal black spots Nematus salicis-odoratus. 



No subdorsal black spots Nematus brunneiis ** 



45. Gall formed in the stem or bud 46 



Gall formed in the leaf. 47 



46. A lateral bud enlarged before it begins to expand in 



spring Euura salicis-orbitalis. 



A round sessile swelling lengthwise on the side of small 



twigs Euura salicis-ovum. 



A gradual enlargement of the twig, five-fourths to twice its iiormalj 



diameter Euura salicis- nodus. 



47. Fleshy, sessile, the shape of a quarter of an 



orange, evenly divided between the two 



surfaces of the leaf Nematus saIicis-desmodioides\ 



Fleshy, globular, sessile, like a miniature apple, .3-. 5 



inch  Nematus salicis-pomum\ 



Subspherical, hollow, growing from a side vein, .2-. 3 



inch Nematus saHcis-pisum\ 



48. Tubercles in a square above the spiracles, more or less distinct . . 4( 

 A single large subdorsal black tubercle ; on Rhus copallina Z\ 



49. Body with a pale subdorsal line 5( 



Body not lined 51 



50. Head black or red ; on Salix Hylotoma clavicornis\ 



Head pale with a vertical dark band Hylotoma virescens (2L)j 



iHylotoma pectoralis. 



51. Head red ; spots distinct; on Betula <. Hylotoma scapularis\ 



^Hylotoma caeruleus. 

 Head black 52 



52. Spots distinct ; on Prunus Hylototna McLeayi (S). 



Spots pale, often dark ringed ; on Quercus cocc'mea 2B. 



'Description imperfect. Possibly not different from the following. 

 ** Described as N, inofiochroma. 



