THE INSECT FAUNA OF THE GENUS CRATAEGUS 1075 



ministra Dru., Datana (Yellow-necked apple caterpillar) 



One of the most destructive species to both native and European haw- 

 thorns during the past few years has been Datana ministra. Very few 

 trees have escaped without at least one colony of these yellow-necked, 

 black-bodied, gray-haired caterpillars feeding on a branch in July and 

 August. Many trees have had an entire branch stripped bare of leaves, 

 and occasionally a whole tree has been defoliated. 



The light brown moths appeared and were found ovipositing during 

 June and July. The clusters of white eggs, each cluster containing from 

 25 to 100, were deposited on the lower side of the leaves and were a common 

 sight in July. The larvae of a colony begin to feed at the tip of a branch 

 and migrate toward its base as they grow, leaving the bare branch behind 

 them. As they become larger they scatter to adjacent branches and feed 

 singly or by twos and threes. They become full-grown and enter the soil 

 in September. 



Several observations were made to determine whether the larvae pre- 

 fer hawthorn to apple. When confined in cages they eat one as readily 

 as the other. In the natural uncultivated areas where hawthorn, apple, 

 and pear grow wild, however, it was noticed that the colonies of larvae 

 were commoner on hawthorn than on the other trees. In one field con- 

 taining 50 hawthorn, 39 apple, and 17 pear trees, 79 colonies of larvae were 

 counted. Of these colonies 56 were on hawthorn, 15 on apple, and 8 on 

 pear. 



Lymantriidae 



leucostigma A. and S., Hemerocampa (White-marked tussock caterpillar) 



The larva of Hemerocampa leucostigma, with its bright red head, its 

 red tubercles on segments 6 and 7 of the abdomen, its four white tussocks, 

 and its three long, black pencils of hairs, is a common sight on both native 

 and European hawthorns. It feeds on the foliage during June and July, 

 and the hairy cocoons are common on the branches in winter. 



Lasiocampidae 



americana Harris, Epicnaptera 



The large larva of Epicnaptera americana is gray with white spots and 

 two red bands above, and orange with a row of lateral diamond-shaped 

 black spots below. It feeds at night on Crataegus punctata foliage in 

 July and August. The species is not common. 



americana Fabr., Malacosoma (Apple tent caterpillar) 



During the years 1917 to 1920, only the old egg masses of Malacosoma 

 americana were found on the twigs of hawthorns about Ithaca. Only two 

 colonies of larvae were seen on the favorite host, wild cherry, and only one 

 colony on apple. 



