20 



replaced by one of these groups, and anterior to each of the inner 

 groups of oval orifices on the pygidium and abdominal segments is 

 another group of circular orifices. Some specimens have the ante- 

 rior group of the second row made up of both circular and oval 

 orifices. The oval orifices are arranged as follows: third row with 

 6 9 orifices in the anterior and 5 8 in the posterior group ; fourth 

 row with 8 10 orifices in the anterior and 8 n in the posterior 

 group. Median group of circumgenital gland-orifices, 21 36 ; anterior 

 laterals, 31 45 ; posterior laterals, 28 32. 



SCALE OF MALE. Plate 3, Fig. IA. Length, i 1.2 mm. 

 Parallel-sided or slightly broadened posteriorly, with the posterior 

 extremity rounded ; distinctly but feebly tri-carinated. Exuvia 

 brown or almost colorless, occupying about one-third the length of 

 the scale. 



REMARKS. 



The nearest relative of C. salicis-nigrae in America is C. lintneri, 

 but the two species may be readily distinguished by the fact that in 

 C. salicis-nigrae the median lobes are rounded while in C. lintneri 

 they are obscurely pointed. C. corni may be readily distinguished 

 by the smaller size, the female scale never reaching the minimum size 

 of C. salicis-nigrae. C. ortholobis and C. longiloba are readily sepa- 

 rated by the fact that the male scales in these two species are with- 

 out carinae. 



C. salicis-nigrae is undoubtedly a native of this country where it 

 has a very wide distribution. It has been sent to me more frequently 

 than any other species treated of in this paper. Prof. Comstock has 

 recorded it at Ithaca, N. Y., and Sc. Louis, Mo., Prof. Osborn at 

 Ames and Davenport, la., and Prof. Cockerell in Nebraska. The 

 Department of Agriculture contains specimens from Mankato, 

 Kansas ; Las Cruces, N. M.; Lincoln, Neb.; Norman, Neb.; Lafay- 

 ette, Ind.; Champaign, 111.; St. Anthony Park, Minn.; New York; 

 West Cliff, Colo.; Pullman, Wash.; Arizona ; Siskiyou Co., Cal. The 

 species has also been sent me from the following localities : Paraje, 

 N. Mex., (Cockerell); Huntington, Mass.: Bedford, Mass.; Lobster 

 Lake, Me., (Kirkland); Maiden, Mass. (Burgess); Lawrence, Mass. 

 (King); Riley Co., Kan. (Parrott); Cobden, 111., and Kappa, 111. 

 (Forbes); Madeira Co., Cal. (Craw); Pullman, Wash., (Piper); Learn- 

 ing, Kingston and Kingsville, Ont., Canada (Fletcher). 



