84 Wisconsin State Horticultural Society. 



checks. Sometimes various insects may multiply to such 

 an extent as to exhaust their peculiar food supply, and in 

 consequence become themselves reduced suddenly to very 

 few. More commonly, as in the present case, an insect has 

 its natural insect enemies, which multiply rapidly as their 

 food increases and so check the depredations of their hosts 

 by eating them up. 



The Maple Bark louse has several insect enemies. One 

 is a minute parasite belonging to one of the lower groups 

 (Chalcididae) of the wasp order. It lives within the body 

 of the adult Bark-Iouse,which it kills and leaves in the spring. 



Beetles of the Lady bird group are very useful in in des- 

 troying other insects. Three species of Lady-bird beetles 

 prey upon the Bark-louse. One of these, Chilocorus bivul- 

 nerus sometimes appears in great numbers upon and under 

 infested trees, crawling over adjacent fences, sidewalks, 

 etc. It looks almost like a little hemisphere, but consider- 

 ably flattened, black, with two red spots (whence the name 

 bivulnerus, twice wounded). 



Before attaining their mature state, they appear as short, 

 dark colored larvae, covered with short spines. In both 

 states of development, they eat the young lice. 



Another kind is Hyperastis signata. The larvge are 

 smaller than those of the preceding, light-colored and cov- 

 ered with down. The mature state is similar to that of the 

 preceding, but smaller. The larvse live in the Qgg masses, 

 one in each, and eat great numbers of eggs. 



The fifteen spotted Lady-bird, Anastis 15-punctata, larger 

 but less plentiful than the other two, is also destructive to 

 the Bark-lice. The larvse are about half an inch long and 

 bear six rows of spines. The mature beetle has a black head 

 and thorax, the remainder of the back brownish- red, marked 

 with fifteen black spots. Length of beetle about one-third 

 inch. 



artificial remedies. 



In some cases it may be necessary to remove badly dis- 

 eased branches. Miss Smith made practical experiments 

 with remedies, and the following recommendations are 

 given: When first hatched, the lice are very tender and 



