102 



KANSAS UNIVERSITY QUARTERLY. 



PYGIDIUM OF FEMALE. 



Median lobes almost fused in basal 

 half; inner margins frequently diver- 

 gent in distal half, serrate. 



Second lobes half or less than half as 

 long as median lobes. 



Space between second and third lobes 

 less than twice the distance between 

 the first and second lobes. 



Third lobe, inner lobule less than one- 

 half inner lobule of second lobe. 



Plates 1, 1-2, 1-2, 1-2, 1-4. 

 Circumgenital glands: Median, 17-21; 



post, lat., 11-27: ant. lat., 21-3.3. 

 In second row dorsal glands, posterior 



group absent. 

 Anteriors 2-6; minute circular glands 



absent. 



Median lobes short, broad, symmetri- 

 cally rounded at tips. 



Second lobes half or more than half as 

 long as median lobes. 



Space between second and third lobes 

 more than twice distance between 

 first and second lobes. 



Third lobe frequently prominent; inner 

 lobule ^one-half inner lobule of sec- 

 ond lobe.i 



Plates 1, 1-2, 1-2, 1-2, 1-5. 



Median, 23-30: ant. lat., 17-53; post, 

 lat., 19-40. 



Posteriors 1-4. 



Anteriors 2-4; 

 1-10. 



minute circular glands 



Chionaspis salicis-nigra', readily separated from C. 07'tholohis by 

 its male scale, can, from observations made upon the pygidia of fifty- 

 four females, be said to differ in this structure by its shorter and 

 broader lobes, by its possession of the posterior group of dorsal 

 glands in the second row, and the j^resence of minute circular glands 

 most abundant in the anterior group, second row, and visible beneath 

 (ventral aspect) the circumgenital glands. In an examination of 

 twenty-seven mounts of ortholohis and twenty-seven mounts of salicis- 

 nigra', I found this posterior group in second -row dorsal glands ab- 

 sent in all ortholohis, and present in all but one salicis-nignc ; this 

 individual salicis-nigrai was well marked with the minute circular 

 dorsal glands. The statement of Comstock- concerning median lobes 

 of ortholohis, "mesal margins are i^arallel for more than half their 

 length," holds good in many individuals among salicis-nigrw. "The 

 distal margin of each (ortholohis) is rounded"- does not always ob- 

 tain, since the inner distal margin is frequently divergent while the 

 outer margin is rounded. 



Chionaspis ntuericand Johnson. Plate XIX, fig. 2. 



Scale of female, 2 to 3.5 mm. in length ; exuviae 0.8 mm. long, sides 

 diverging ; generally straight, sometimes curved to right or left, curved 

 scales located singly, broadly convex, dirty white. 



Scale of male, tricarinate, 0.7 to 1 mm. in length, sides nearly par- 

 allel, clear white ; exuvise pale lemon yellow. 



Mature female. The pygidium bears three pairs of lobes. Median 

 lobes prominent, fused almost entire length of inner margins, slop- 

 ing rapidly laterad, lateral margins with from one to three distinct 



1. Cooley says "third pair often almost obsolete." Sp. Bull. Hatch Exp. Sta. Aug. 1899, p. 

 19. When this is the case lobes 1 and 2 are proportionately depressed. 



2. Kept. U. S. Comm'r Agr. 1880, p. 317. 



