IN'ew York ActKicultukat. Experiment Station. 299 



Weed has stated, accounts in part, at least, for the large numbers 

 of caterpillars that are seen crawling np the trunks of infested 

 trees. Observations upon caterpillars in confinement showed that 

 much less silk is spun after the last molt while crawling about 

 than duriuG' the earlier stages. 



Sharing a nest luith the apple-tree tent-caterpillar. — What is 

 probably a very unusual occurrence is shoAvn at Plate XXII, fig. 1. 

 This nest was made by a colony of apple-tree tent-caterpillars. 

 It will be observed that most of the caterpillars in sight are not 

 the rightful o^u-ners of the nest, but are forest tent-caterpillars. 

 The two species can be easily distinguished as the apple-tree tent- 

 caterpillars have a conspicuous white line extending the whole 

 length of the back, while the forest tent-caterpillars have the line 

 replaced by a row of white spots. This nest was on an apple 

 tree near the Station grounds. At the time this picture v\'as 

 taken, about 10 :30 a. m., the caterpillars had collected on the 

 sunny side of the nest. There were none on the opposite side. 

 The writer watched this nest for several days and it was observed 

 that the '' guests " went out regularly with the other species 

 to feed and returned with them. Upon no occasion, however, were 

 the forest tent-caterpillars seen to enter the nest. Upon the 

 fourth day the nest was cut open and although it was well filled 

 with apple-tree tent-caterpillars none of the forest tent-cater- 

 pillars could be found. A few days after these observations were 

 made ]\[r. G. G. Atwood reported finding a similar case in an 

 apple orchard a few miles distant. Although it is not uncom- 

 mon to find two or three stray forest tent-caterpillars upon one 

 of the nests of their near relatives, such cases as the above appear 

 to be quite imusual. 



Congregating habit. — A very noticeable habit is that of con- 

 gregating in large numbers on the trunks and branches of the 

 infested trees. There appear to be two principal occasions for 

 this, first, when resting during the heat of the day and, second, 

 when about to molt. As an indication of the former, the writer 



