THE ZIMMERMAN PINE MOTH. 
THE PUPA. 
Freshly formed chrysalids are of a light brown color, which changes 
to blackish brown as the moth within develops toward maturity. 
The chrysalis is cylindrical, about three-fourths of an inch long, 
rather slender, and without spines on the segments. This last char- 
acter makes it readily distinguishable from a sesiid pupa, which is 
frequently found under somewhat similar conditions. 
SEASONAL HISTORY AND HABITS. 
While adults emerge and mate from about May 1 to September 15, 
the maximum flight of the moths occurs during the month of July. 
They appear to be rather long lived, many 2-weeks-old specimens 
reared in the laboratory being as ready to take wing when disturbed 
as when they had just burst the bonds of the chrysalis. No other 
species of moths reared in captivity the larva? of which feed on 
internal tree tissues were observed to live more than 10 days after 
emergence under similar conditions. The longevity of the Zimmer- 
man moths evidently extends the period of mating beyond the 
general flight, and consequently fertilized eggs are deposited during 
any of the milder months. 
Larvae of all sizes, except the most minute in winter, may be found 
at any time of the year. 
Though frequently but a single larva is found in a wound, the 
writer is of the firm opinion that eggs are almost invariably depos- 
ited in clusters. In the many observations while the larva was less 
than three-eighths of an inch in length six or more of them were 
always found in one infested spot. From a specimen of yellow 
pine 6 inches in length and but 1 inch in diameter showing old work, 
which was placed in a breeding cage during the middle of December, a 
month and a half after heavy frost had ended all outdoor insect 
activity, seven larvae emerged early in January from eggs which had 
evidently been deposited on this small specimen during the previous 
late autumn. (PL II, fig. 3.) 
Again, it is often the case that a space a foot or more wide and 
several feet long on a tree trunk has the cambium literally honey- 
combed with the tunnels of numerous larvae. In one such case the 
writer found 27 nearly mature Pinipestis larvae at work. 
In mature stands, in " spike-tops" in the making, and at the bases 
of new spikes, plural infestation is evidently the rule. 
This conclusion is verified to some extent by the observations of 
Mr. W. D. Edmonston at the Forest Insect Field Stations at Ashland, 
Oreg., and later at Colorado Springs, Colo., and by quite a number of 
larvae and valuable notes that he sent to the writer. These notes 
generally end with the statement: " Under bark in hardened pitch 
