304 BOARD OF AGRICULTURE. [Pub. Doc. 



kinglets, feed on smooth-skinned caterpillars, while at least 

 fifty species are now known to feed on the spiny and hairy 

 caterpillars. It is largely due to a lack of native birds that 

 the shade trees in our cities are so overrun with caterpillars. 

 While the imported sparrow keeps down the span worms, it 

 does not check many other pests. When the imported 

 leopard moth appeared in New York and Brooklyn, causing 

 great havoc among the trees in the parks, it was feared that 

 as the insect spread it would become a serious enemy to the 

 trees of the entire country. But I am informed by Dr. J. 

 B. Smith, State entomologist of New Jersey, that this moth 

 is doing little damage in the country districts, where the 

 native birds seem to keep it in check. At first it looked as 

 if the large larvfe would escape the birds, because of their 

 habits. They are borers, beginning life within the small 

 twigs, and when these quarters get too narrow for them, they, 

 eat out and crawl down outside to larger twigs. It is then 

 they are taken by many native birds, though the imported 

 sparrows do not appear to check tkem. Dr. Smith says that 

 the woodpeckers eat the female moths, and probably drag 

 the young larvae out of the smaller twigs. The American 

 silkworm, the larvce of Telea j^ohjphemus, is one of the 

 largest and most voracious of our caterpillars, and, should it 

 increase as rapidly as the gypsy moth, it would become a 

 fearful pest ; but it is noticeable that this and other allied 

 species of great size never reach a destructive height. The 

 principal reason for their scarcity is that they are eagerly 

 eaten by birds. Hawks, owls, goatsuckers, woodpeckers, 

 jays, robins, tanagers, blackbirds and other species capture 

 these large caterpillars. When Mr. Leopold Trouvelot was 

 engaged in raising American silkworms at Medford the 

 robins came from all quarters to destroy them, and gave him 

 more trouble than all other birds combined. 



Mr. Trouvelot says that one of these caterpillars will con- 

 sume in fifty-six days not less than 120 oak leaves, weighing 

 three-fourths of a pound, drinking in the mean time not less 

 than one-half ounce of water, the weight of the food eaten 

 being 86,000 times the weight of the worm on the first day. 

 During this time it has increased in weight 4,140 times. The 

 destructiveness of the species if allowed to increase may be 



