New York Agricultural Experiment Station. 377 



Predaceous insects. — Several species of predaceous insects feed 

 upon the caterpillars, usually attacking them when crawling down 

 the trunk of the tree or upon the ground in search of a suitable 

 place to spin their cocoons. Among the most important in this 

 State are the large ground beetles, Calosoma scrutator Fab. and 

 Calosoma calidum Fab., and the spiny soldier bug, Podisus spino- 

 sus Dallas. Although these insects are very voracious and feed 

 readily upon the caterpillars they are not usually sufficiently 

 abundant to materially lessen their numbers. 



Parasitic insects. — Of much more importance than the preda- 

 ceous insects as a check to the apple-tree tent caterpillar are 

 the parasitic insects which prey upon it. Both the eggs and cater- 

 pillars are attacked, as at least one species, Telenomus clisiocampae 

 Riley, 12 is known to prey upon the eggs. 



Parasites attacking the caterpillars usually occur in sufficient 

 numbers to. be of some real value in checking the increase of the 

 species. These useful little insects were evidently very abundant 

 last summer. Out of 559 cocoons collected by the writer and 

 brought into the laboratory, only about 20 per cent produced 

 moths leaving 80 per cent victims of the parasites. The following 

 species were bred from the cocoons, Pimpla conquisitor Say (Plate 

 XXXIII, Fig. 3, male and female natural size) 13 Pimpla con- 

 quisitor var., Pimpla pedalis Cr., 14 Theronia fulvescens Cr., 14 

 Spilocryptus (Cryptus) extrematis Cr., Mesotenus sp., 14 Dibrachys 

 baucheanus Ratz., was also reared in small numbers but this is a 

 secondary parasite. In addition to the above Pimpla annulipes 

 Brulle, Theronia melanocephala Brulle, and according to Felt, 15 

 Apanteles congregatus var. rufocoxalis Riley and the parasitic fly, 

 Frontina frenchii Williston, are known to prey upon this insect. 



Diseases. — At least one well-marked disease sometimes reduces 

 the number of these tent caterpillars. It is bacterial in its nature 



12 U. S. Natl. Museum Bui., 15, p. 450. 



13 Determined by Miss A. M. Beach. 



14 Determined by Mr. W. H. Ashmead through courtesy of Dr. L. O. Howard. 



15 N. Y. State Mus. Bui. 23, vol. 5, p. 183. 



