; . : d COURTESY CONN. AGR. EXPT. STA. 
FIGURE 191.—Larvae of Trichiocampus viminalis on leaves of poplar. 
Older ones tend to scatter and eat all but the midribs and larger 
veins. They become full grown in June or early July. Some pu- 
pate and give rise to a second generation of adults in August; 
the remainder do not complete their development until the follow- 
ing spring. Carolina and Lombardy poplars grown for ornamental 
purposes may be seriously defoliated. 
The dusky birch sawfly, Croesus latitarsus Norton, occurs in 
eastern Canada and south through the Eastern States to Florida. 
Its hosts are various species of birch, preferably gray birch. It 
has also been found feeding on alder and cherry in Canada. Full- 
grown larvae are yellowish-green with shades of black and are 
about 24 mm. long. There is a row of more or less distinct black 
blotches on each side and a series of black spots in the subspirac- 
ular area. 
Winter is spent in the prepupal stage in a cocoon in the topsoil. 
Adults appear during May and June, or earlier in the Deep South. 
There may be several overlapping generations per year and lar- 
vae may be found from spring until fall. The larvae are gre- 
garious and feed along the edges of the leaf (fig. 192). Colonies 
are often found defoliating small saplings, but this usually does 
not occur over wide areas. 
COURTESY CONN. AGR. EXPT. STA. 
FIGURE 192.—Larvae of the 
dusky birch sawfly, Croe- 
sus latitarsus. 
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