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 overlap- 
ping generations per year and larvae may be found from spring until fall. The larvae 
are gregarious and feed along the edges of the leaf (fig. 196). Colonies are often 
found defoliating small saplings, but this usually does not occur over wide areas. 
Other species of Croesus include C. curvarius Smith on hazel, C. castaneae 
Rohwer on chestnut, and C. varus (Villaret) on alder, the latter sawfly of foreign 
origin. 
2 
Courtesy Conn. Agric. Exp. Stn. 
Figure 196.—Larvae of the dusky birch sawfly, Croesus 
latitarsus. 
The striped alder sawfly, Hemichroa crocea (Geoffroy), probably an introduced 
species, occurs from coast to coast in southern Canada and the Northern United 
States south to New Mexico. Its hosts include various species of alder and occasion- 
ally birch, hornbeam, and willow (//0/). Full-grown larvae are yellowish and about 
20 mm long. The head is shiny black, and there is a dark-brown subdorsal stripe on 
each side running from the second thoracic to the tenth abdominal segment. Two 
broken subspiracular stripes composed of blotches and dashes extend along each 
side to the ninth segment. 
Winter is spent in the prepupal stage in cocoons just beneath the surface of the 
soil. The cocoon is very thin-walled and is formed within a cell made by cementing 
together particles of soil. Adults appear during late May and deposit their eggs in 
slits cut in the sides of the midrib on the undersurface of leaves. The larvae are 
gregarious and usually eat all but the midrib and larger veins of the leaf. They 
become full grown in July, and adults of a second generation appear during late July 
and August. Larvae of this generation are found during August and September. 
There are two generations per year. This species occasionally severely defoliates 
alder in the Lake States, Northeastern States, and Canada. 
The maple petiole borer, Caulocampus acericaulis (MacGillivray), is known to 
occur in Ontario, Connecticut, New York, Maryland, Michigan, Illinois, and 
Alabama. The larvae feed by boring into and tunneling the petioles of maple leaves. 
Full-grown larvae are light yellow with light-brown heads and are about 8 mm long. 
Winter is spent in the prepupal stage in a cell 5.0 to 7.5 cm below the surface of 
the soil. Adults appear early in May and deposit their eggs near the bases of the 
407 
