108 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
FIELD KEY TO THE GENERA OF SCALE INSECTS BASED PRINCIPALLY ON 
HOST PLANTS—Continued 
2 (1). On hardwoods (see appropriate host) —Continued 
Tulip tree twigs and branches, sometimes on magnolia and 
poplar; mature female hemispherical; 5 to 8 mm. in diameter; 
Colomaarks Drowns sas =e Toumeyella, in part (p. 144). 
3 (2). On pines (five alternatives) 
Hard pines at base of needles on new growth during summer; 
mature female oval; woolly wax covering | em. or more in 
length; color of woolly covering white 
Pseudophilippia (p. 144). 
Seotch, jack, lodgepole, and other hard pines on twigs and 
branches; mature females oval; 5 to 7 mm. long; color reddish 
brown; dorsal surface very convex and pitted or irregular 
Toumeyelka, in part (p. 144). 
Hard pines on new shoots and under bark scales; mature female 
long oval; 2 to 4 mm. long; color dark brown to black; 
producing long flat white egg sac under bark scales of 
branches and trunk; immature instars causing small pit 
galls in epidermis of new growth; new growth dying in July, 
August;-and September_22_-_2= ===]. -2 Matsucoccus (p. 1389). 
Pine leaves, various species; mature female pear-shaped; 
1% to 3 mm. long; color dirty white to dirty gray 
Phenacaspis (p. 149). 
Pine, various species, and Douglas fir leaves; mature female 
oval; 1 to 2 mm. long; color dark gray; concentric nipple 
OTAGO tt ee eee Aspidiotus, in part (p. 148). 
On other conifers (four alternatives) 
Arborvitae twigs; mature female, round to oval; 3 to 4mm. 
long; color reddish or reddish brown, sometimes mottled; 
dorsal surface very convex ___-_-_- Lecanium, in part (p. 145). 
Hemlock leaves and twigs; mature female oblong; 1 to 2 mm. 
long; color dark gray to black with lighter border 
Aspidiotus, in part (p. 148). 
Juniper leaves and twigs; mature female nearly circular; about 
2 mm. in diameter; color light gray to white; central or 
concentric nipplesyellowa 2] ==2 eee Diaspis (p. 151). 
Spruce, various species, at base of buds on new growth; mature 
female round; 3 to 4 mm. in diameter; color light brown; 
dorsal surface very convex________-_-_ Physokermes (p. 147). 
4 (1). Body of adult female covered by a “‘seale’’ made up of secreted 
matter plus the cast skins of the two larval stages___________ 
Body of adult female otherwise, as naked, covered with waxy or 
woolly secretion, enclosed in a secreted shell, never covered by 
a scale-as describedtabovess == = es 2 ee es 
5 (4). Seale of adult female elongated, narrowed anteriorly with the 
larval cast-skins terminal, broadened posteriorly_____________ 
Seale of adult female circular to oval with exuviae central or 
SUDCEnib Taliesin er em Aspidiotus, in part (p. 147). 
6 (5). Seale of adult female white or dirty white 
Chionaspis, in part (p. 149, 151). 
Seale of adult female dark, usually dark brown 
Lepidosaphes (p. 151). 
7 (4). Body small, not exceeding 2 to 3 mm. in diameter, enclosed in a 
thin transparent shell with a fringe of secretion around margin 
Asterolecanium, in part (p. 142-148). 
Body not enclosed in a shell, mostly considerably larger, 4 mm. 
OF TOME a Sa ee ee 
8 (7). Adult female at maturity with body remaining soft, fringed at 
hind end with a large ovisae showing conspicuous flutings 
Icerya (p. 189). 
Body at maturity becoming hard and eventually brittle; ovisac, if 
present, loosely formed: motilmted= S22 eee es ee es nee ee 
9 (8). With a short, stout posterior ovisac______-_- Pulvinaria (p. 148). 
Body naked at maturity, eggs deposited beneath it 
Lecanium (p. 145). 
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