Dyar.l 
400 
[No 
they furnish (rood family characters, paralleled only in two other 
families (the Drepanidae and Dioptidae). In the Thyatiridae, 
tubercles 4 and 5 are situated in line on the central segments, 
and there is a secondary tubercle above the spiracle, associated 
with tubercle 3. These characters will presumably be found to 
obtain also in Pseudothyatira and Bombycia which I have not 
examined. 
Thvatira scripta Gosse. 
Egg. — Laid at the apex of one of the serrations of a black birch leaf on 
its side, the apex pointing outward. Melon-shaped with 14 ribs, ending 
irregularly, some reaching the micropyle, others not ; cross striae distinct, 
the cells three times as wide as long, rectangular, the ends just indicating 
scallops on the ribs. Base quite similar to micropyle. Color yellowish 
white, shining; size 0.65x0.5 mm. 
First larval stage. — Head slightly bilobed, nearly black ; width 0.3 mm. 
Body enlarged a little at joints 3 and 12, smooth, transversely creased, uni- 
form brown of a rather dark shade. Feet normal, all used in walking, 
but the anal pair held up in rest. Feet dark; anal plate small, black. 
Tubercles 4 and 5 in line (Fig. 2), but on joint 11, tubercle 4 is a littl* 
Fig. 2. Tubercles of Thyatira scripta, first stage. 
higher than 5, and on joint 12 it is remote from it and quite behind the 
spiracle. The larva sits on the extreme edge of a leaf (like Notodonta 
stragula) or on the back of one. 
■ Second stage. — Sits on the upper side near the edge of a leaf, the head 
down and thorax contracted, tail elevated; drops off by a thread when 
disturbed ; eats little patches on the upper side of the leaf near the edge. 
Width of head 0.6 mm. All brown, or greenish, overwashed with brown 
of an ill-defined shade, marked as in the next stage, but faintly. Tubercles 
black ; setae short. Subventral region vinous-brown. 
Third stage. — Position as before, greatly resembling that of Falcaria 
bilineata. Joints 3 and 4 a little folded transversely dorsally, suggesting 
prominences ; joint 12 a little enlarged. Feet normal, the anal pair 
