200 SPAN-WORMS. 
great annoyance to people passing under such trees. In this 
manner they are also carried by passing vehicles to places 
not yet invaded by them. As soon as they reach the ground 
they burrow init to a depth of from two to six inches and 
there they form a rather tough cocoon of buff colored silk 
interwoven with particles ofearth. The pupa is about half 
an inch long, of a light grayish-brown color; that of the 
male is slender and furnished with wing-cases. The pupe 
remain in the ground until late in autumn when the moths 
emerge. 
ReEMEDIES.—With the exception of the one species of 
eanker-worms so destructive to forest trees in the lake 
region of Minnesota these insects are not as yet of a threat- 
ening nature in our state. Both species are found, however, 
and it is simply a question of time when they wiil become 
more numerous. At present orchards are by no means 
found near every farm house, but the time is rapidly coming 
when this will be the case, and with more orchards the large 
number of injurious insects living in them will also become 
more numerous and destructive. These insects are rather 
easy to destroy with any of the arsenical preparations; in 
fact they were about the first tree-infesting species that 
were destroyed by these means. But in case of large trees it 
is not easy to apply them, and here we have to apply other 
remedies based upon the fact that the wingless females have 
to ascend the tree to deposit their eggs, which we can and 
should prevent. Prof. Saunders writes: ‘‘To attack an 
enemy with success, it is essential that we know his vulner- 
able points. In this instance since the females are without 
wings, ifthey can be prevented from crawling up the trees 
to deposit their eggs, a great point will be gained. Various 
measures have been employed to secure this end, all belong- 
ing to one or other of two classes, first, those that prevent 
the ascension of the moth by entangling her feet and 
holding her there, or by drowning her; second, those which 
look to a similar end by preventing her from getting a foot- 
