SHADE TREE INSECTS 41 



The eggs are seldom observed. They are deposited in masses of 300 or more 

 on the under side of the leaves. The individual eggs are less than 1/35 inch in 

 diameter, elongate, and round, approaching cylindric with somewhat flattened 

 apex. The color is dull white; the surface is somewhat roughened and has regular 

 markings. 



The newly hatched caterpillars have black heads and brick-red bodies with 

 faint stripes. As they become older, the brick-red color deepens, the lines become 

 more distinct, and long sparse hairs appear. The mature caterpillar is a little 

 over 2 inches long. The body is black, very indistinctly lined, and covered with 

 a considerable number of long white or grayish-white, frowsy hairs. 



The pupae are found below the surface of the ground near their host trees. 

 The}' are a little over Y2 inch long, hard, and dark brown in color. 



Lije History. The moths usually are abroad in Juh'. Soon after emerging 

 they lay their eggs in masses of about 300 on the under side of the leaves. These eggs 

 hatch in a week or ten days, probably in late July or early August in this region. 

 The >oung caterpillars feed in clusters on the foliage, at first skeletonizing the 

 under side but later consuming the entire surface of the leaves. At certain times 

 during this feeding period they congregate in masses on the trunk or larger 

 branches and shed their skins, after which they soon return to the foliage to feed 

 again. The masses of hairy, cast-off skins remain on the tree for a while, pre- 

 senting an unsightly appearance. The caterpillars retain the gregarious habit 

 until fall approaches when they are almost mature and read\ to pupate, at which 

 time they wander about for a few days. They then go to the ground, burrow 

 beneath the surface, and transform to naked pupae, in which stage they pass 

 the winter. Transformation to the adult stage takes place the next season. 

 There is only one generation a year in this vicinity; farther south there may be 

 two or three. 



Co}itrol. The caterpillars may be destroyed on valuable shade trees bj' spray- 

 ing the foliage thoroughly with lead arsenate in the proportion of 4 pounds to 

 100 gallons of water with 2 pounds of flour or 1 pound of calcium caseinate as a 

 sticker. This should be applied when the caterpillars begin to feed. 



The caterpillars feed gregariously, often on one limb. If the infested branch is 

 a small one, it can be removed without injur\- to the tree and the caterpillars 

 destroyed. 



Sometimes the clusters of caterpillars which are shedding their skins on the 

 trunk or limbs may be crushed or otherwise destroyed. If this is not done until 

 the older caterpillars are shedding their skins, some injury to the foliage will have 

 already occurred. 



Baerg, W. J. Ark. Agr. Exp. Sta. Bui. 224:9-15, 25. 1928. 

 Britton, W. E. Conn. State Ent. Rpt. 17:326-328. 1918. 

 Felt, E. P. N. Y. State Mus. Mem. 8(1) :303-305. 1905. 

 Houser, J. S. Ohio Agr. Exp. Sta. Bui. 332:226-229. 1918. 



Yellow-Necked Caterpillar 



Datana ministra Drury 



This insect is widel}^ distributed in the United States. It is common in the 

 northeastern United States and is also present on the Pacific Coast. Although 

 it is primarily an orchard pest, the caterpillar occasionally causes considerable 

 injury to the foliage of some shade and ornamental trees. Its attack occurs from 

 midsummer to late summer. This insect, like the closely related walnut cater- 



