77 



the streets in early June, although during- previous years great num- 

 bers were to be seen at that time. There were also comparatively few 

 moths to be found later in the season. 



This wholesale destruction of the Clisiocampa larvae must have 

 brought about also a very general destruction of the parasites of 

 these caterpillars. In 1897 Mr. Fiske and myself had begun an inter- 

 esting study of these parasites, observing many facts regarding the 

 curious interrelations of host, primary, secondary, and tertiary parasites, 

 which we hoped to complete in a measure this season ; but the microbes 

 interfered with all that. 



Our 1897 studies showed, however, that Pimpla conquisitor was much 

 the most abundant parasite. Several hundred adults of this species 

 were bred, which appeared to have attacked the occupants of at least 

 half the large number of Clisiocampa cocoons collected. Tjie eggs 

 appear to be deposited in the full-grown caterpillars and to be devel- 

 oped into larvae that do not emerge from the host until the latter spins 

 its cocoon. The pupa stage of the parasite lasts from five to seven 

 days. The most abundant secondary parasite preying upon Pimpla 

 conquisitor was Theronia fulvescens, which was reared in considerable 

 numbers. Mauy other parasites were reared and studied, accounts of 

 which we hope soon to record in a bulletin of the New Hampshire 

 College Experiment Station. 



Various experiments with remedies brought out little new informa- 

 tion. The careful use of a very small amount of kerosene (a teaspoon- 

 ful to a nest) in wetting the silk of the nest was found a satisfactory 

 way of killing the partially grown caterpillar; but care is needed, as 

 if sufficient kerosene is added to saturate the bark the tree is injured. 

 One of the most satisfactory remedial measures that came to my notice 

 related to the removal of the egg clusters. In the village of Newfields, 

 N. H., the improvement society offered the school children 10 cents a 

 hundred for all the 'egg masses, or " caterpillar's belts" as they are 

 locally called, that they would bring in. Many of the children worked 

 faithfully, and when in February I was called to point the moral of 

 the process I found that 8,250 of the egg masses had been obtained. 

 I doubt if the expenditure of $8.25 by a village improvement society 

 often does more good than was done in this case. The caterpillars 

 were destroyed, and the effect was easily noticeable in the spring and 

 early summer, while the boys and girls had a remarkable lesson in 

 nature study. 



A more serious outbreak than that of the American tent caterpillar, 

 because more sweeping in its character, is that of the forest tent cater- 

 pillar (Clisiocampa disstria), which has gradually been developing in 

 New England during the last three or four years. At present the 

 attack is most severe in New Hampshire in the Connecticut Valley, 

 where a great deal of damage has been done over an extended area, but 

 there is evidence to show that the insect is gradually increasing in 

 many regions away from this valley. 



