SUBFAMILY APHINAE 189 
Laing (1921:125), after examination of typic specimens sent him by Gillette, 
writes “there seems to be no valid reason why the two species (adjuvans and 
polygoni) should not be the same.” 
Aspidaphis adjuvans sub. sp. rowei Knowlton and Smith 
Aspidaphis adjuvans sub. sp. rowei Knowlton and Smith, 1936g:777. 
This species is so close to A. adjuvans (Walker) (Syn. A. polygoni Gillette) 
that drawings and descriptions seem unnecessary. The differences as compared 
with Gillette’s description of polygoni and paratype specimens are very slight 
and as follows: Longer hind tibia (.77 instead of .55-.63) and longer hind tarsal 
II (.15 instead of .11-.12), shorter cornicle (.06-.07 instead of .07-.08), fewer sen- 
soria (4-5, instead of 6-8) on III of alate vivipara, different host plant (Chryso- 
thamus instead of Polygonum). Indeed, if it were not for the radically. different 
host plant it would hardly be advisable to give this form a separate name. 
Furthermore, an alate specimen has been taken on Polygonum subsequent 
to the original description by Gillette, which agrees with the form from Chryso- 
thamnus in tibial and tarsal length (the only appreciable distinction). Evidently 
either the Chrysothamnus form also occurs on Polygonum unless this instance 
was accidental or the two apparent forms are but variations of the same species. 
Biological experiments are needed for further evidence. 
Collections. On Chrysothamnus nauseosus subsp. nauseosus. Utah: Kanosh 
and Clover. Alate vivipara May 3, oviparae Oct. 2. 
Cotypes. Knowlton and C. F. Smith Collections. 
Aspidaphis aquatica (Gillette and Bragg) 
The Armoured Water Aphid 
Siphocoryne aquatica Gillette and Bragg, 1916:447. 
Aspidaphis aquatica, Gillette and Palmer, 1932b:457. 
Apterous Summer Vivipara. Light yellowish green; heavily powdered ventrally; antenna 
blackish on distal half; cornicle and legs pale; cauda pale or dusky to blackish; legs appear- 
ing powdery. Tergite VIII projecting backwards nearly to tip of cauda and rather triangular 
and shield-shaped. Size of body 2.60 by .7-1; hind tibia .85-.90; hind tarsal II .17; antenna 
.85-.95, sensoria faint; rostral IV+V rather broad, barely attaining 2d coxa. Dorsum of body 
Fig. 219. Aspidaphis aquatica 
Alate Vivipara. Head and thorax blackish; abdoment light yellowish green with dusky 
bands and blotches on most of segments, often coalesced into a dorsal patch on II to V in- 
clusive. Body length 2; hind tibia .9-1; hind tarsal II .18; antenna 1.10, secondary sensoria 
irregular in size; rostrum attaining between 1st and 2d coxae. Hairs blunt or slightly capitate; 
on hind tibia .01 to .015; cornicle clavate, without flange and with opening towards median 
side of tip, faintly imbricated, weak and held against body, recumbent. Cauda parallel-sided to 
long-tapering, bearing 3 pairs of lateral hairs. Abdominal VIII with wartlike dorsal tubercle. 
Collections. On leaves and stems of Catabrosa aquatica, often beneath the 
surface of the water. Colorado: Fort Collins and Denver. Alate and apterous 
viviparae all months of the year; common. 
Type. U.S.N.M. Paratypes, Colo. Agr. Exp. Sta. Collection. 
