186 SPAN-WORMS. 
objects should be able to withstand the rain, snow and cold 
of our winters without the slightest injury. All states of 
this insect are shown in Fig. 185. 
THE CHAIN-DOTTED GEOMETER. 
(Caterva catenaria Cram. ). 
The moths of this interesting geometer appear some- 
times in such very great numbers as to look like a snow- 
storm andonthat account greatly alarm the people. But us- 
ually they are not very common for a number of years, when 
for somereasons, perhaps absence of parasites, or assisted by 
suitable climatic conditions, they again appear inlarge num- 
bers. Here in St. Anthony Park the moth can always be 
found flying about during the middle part of September; the 
moths are diurnal, but fly in a rather uncertain manner and 
only for short distances, so that a trained eye immediately 
recognizes that they are not genuine butterflies. The moth 
is easily recognized by its large size and by its snow-white 
thin wings, marked with numerous black spots, which are 
Fig. 186.—Caterva catenaria Cram. After Packard. 
arranged in two more or less plainly marked scalloped lines; 
in some cases the spots are dashes, which connect with the 
neighboring ones, thus forming continuous lines. There is 
always, even in very pale specimens, a distinct discal spot. 
The fringe of all wings is checkered with black dots. The 
head is ochreous-yellow in front; the thorax yellowish at 
the base of the shoulder-covers The male has a yellowish 
