33 
days; (levelopiiu'iit of tlu^ i)iii)a, 12 days; total, 57 to (>() days, or i wo 
months. 
A i'ow days after liavin^- left tlio pupa, tlie iiiui^o is ready lor ovipo 
sitioii. 
Often the caterpillars, Avhich have Just left tlie ejjj's, let themselves 
down by means of a. lon*^- thread, in order to reaeh other leaves. Dur- 
ing- the suspension they are easily carried oil" by the wind and tiius 
become widely spread. 
Fortunately, very often the eo<.s are infested by two parasites, viz, 
Ccraphron hvncficicns Zehut., and Chaiosticha nana Zehnt. The infested 
egos turn to black or dark brown. Besides, the eggs are destroyed by 
the larva' of a species of Obrysopa, which sucks them out. 
SCIRPOPHAGA INTACTA, SNELL. 
The female of Scirpophaga intacta lays her eggs in little clusters, and 
as a rule on the underside of the leaves. These egg-clusters are from 
(i to 10""" long, composed of 15 to 30 
eggs, and are covered with abundant 
cinnamon colored hairs, so that the eggs 
themselves cannot be seen. The total 
number of eggs produced by one female 
is 00 to 70. 
The freshly hatched cater i)illars are 
dark browu in color and are about 2.5"'"' 
long. They penetrate the shoots from 
above (say a single larva in each shoot), 
following in the beginning the midrib 
of the young unfolded leaves. Farther 
beneath they eat completely out the 
heart of the shoot. Finally, they attack 
the stalk, making a straight descending 
gallery or tunnel, which varies in length 
according to the individuals. When the 
larva is nearly full grown the gallery is 
bored horizontally outward by means of 
a gentle curve. Then the dust is re- 
moved from the lower i^art of the gallery 
(i.e., pushed upward), and the gallery is 
closed before and behind the larva with three or four transverse silken 
membranes spun by the larva. Thereupon this latter transforms to 
pupa. 
The whole development is accomplished within the following periods: 
Egg state, 8 to 9 days; larval state, 32 to 35 days; pupal state, female, 
8 to 10 daysj male, 10 to 12 days; total, female, 48 to 54 days; male, 
50 to 56 days. 
In penetrating the stock the larva destroys always the growing veg- 
11930— No. 10 3 
leuf- 
FlG. 10.— Scirpoi^hafja intacta: 
grown larva at left — enlarged ; 
Ijlatle with egg-mass at right — natural 
size (after Zehntner), 
