NATURAL CONTEOL. 49 
wireworms were removed just as soon as they showed traces of the 
disease. In spite of all these precautions the disease spread un- 
checked until, within 10 days of its appearance, it had killed every 
wire worm in the petri dishes, to the number of about 1,000. 
The disease spread in the same way every time, and the wireworms 
kiUed by it were so characteristically colored that they could never 
be mistaken. When a larva became diseased, there was a very faint 
reddish coloration in the anterior portion of its body. When placed 
under the microscope, it looked as if the head and thoracic segment 
contained Uttle, brilliant red, oil globules. The following day the spec- 
imen would be a deep blood-red all over its body and so putrid that 
when picked up on a pin point it would fall to pieces. The larvae 
immediately surrounding it would show the faint red coloration and 
the following day they would be red and putrid, while the larvae 
nearest them would be showing signs of infection. When the dishes 
were not sterilized, all the larvae in a dish would be killed in from 
three to four days. 
That the red bacterium was the cause of the trouble was very 
strongly suggested by the fact that whenever one infected ware worm 
was placed in a sterile cage the disease immediately made its appear- 
ance. This was further borne out by the fact that where a whole 
infected wireworm was used to make a culture on agar, a pure culture 
of the red bacterium almost invariably resulted. When the cultures 
were made on agar, the colonies showed in their true color — a beau- 
tiful rich blood-red. (See PI. VIII, fig. 1, p. 20.) 
It is interesting to note at this time that the mature wireworms 
which were exposed to infection by this bacterium were never affected 
by it. 
Everything considered, the larvae of Limonius californicus ^eem to 
be affected very little by their animal enemies and by their fungous 
and bacterial diseases, even when these latter are working under 
favorable conditions. 
Fungi Affecting the Pup^ and Eggs. 
A few piipae in the laboratory were attacked by a fungus and pre- 
sumably kiUed by it, as they died a short time afterward. As this 
occurred only in two cages and as no fungus-kiUed pupae were found 
out of doors, it is probable that this infection only occurs under arti- 
ficial conditions. Even if it did occur in the fields it would spread 
slowly, for during the time the insect is in the pupal stage the humidity 
is low and the soil in the fields is rather dry. 
A fungus which attacked and killed some of the eggs of Limonius 
californicus in the rearing cages in the laboratory would probably 
seldom or never occur out of doors. Even if it did it would not be 
6140°— Bull. 123—14 4 
