December, '09] JOURNAL OP ECONOMIC ENTOMOUOGY 451 



moth in Massachusetts, and to the agents and employees of the Bureau 

 of Entomology, similarly employed in Massachusetts and New Hamp- 

 shire. 



Although exact comparisons are, of course, impossible, there is little 

 doubt that cecropia is very much less common in southeastern New 

 England than it was in those sections of Long Island and New Jersey 

 from which Dr. Smith secured his material. The collection in eastern 

 Massachusetts or southern New Hampshire of as many as 1,000 cocoons 

 would have been an almost herculean task. The total number of 

 cocoons received from a considerable number of men regularly en- 

 gaged in field work, w^ho were instructed to collect and forward to the 

 laboratory any that they might find, was only 370, without counting 

 those a year or more old. In addition there were 997 cocoons of 

 promethea and 40 of polyphemus. 



Material was received from a large number of towns, scattered over 

 a territory of considerable extent. A few more from the shores of 

 Buzzard's Bay, many from the more central sections of the state east 

 of Worcester, but the larger number from the northeastern towns, 

 along the shore and in the lower valley of the Merrimac. The New 

 Hampshire material was nearly all from the valleys of the Merrimack 

 and Suncook rivers. 



Comparison between the cocoons of cecropia received from these 

 various localities and those studied by Dr. Smith as regards the 

 prevalence of parasitism, death through other causes, etc., is interest- 

 ing, and is as follows : 



New Jersey and Long Island Mass. and New Hampshire 

 Number Per cent Number Per cent 



With healthy pupse 

 Dead but not parasitized 

 Parasitized 



Total 1,028 100 370 100 



It will be noted that the percentage of parasitism in the two lots is 

 not particularly different, but that the proportion of healthy pupae in 

 Massachusetts and New Hampshire is very strikingly larger. This is, 

 apparently, a confirmation of Dr. Smith's conclusions concerning the 

 relative effectiveness of parasites versus other causes in the control of 

 this insect, and would seem to support the theory that the parasites 

 were less mobile, and therefore less active agents in natural control. 

 A comparison between the condition existing in Massachusetts and 

 New Hampshire, respectively, in the winter of 1908-1909 does not sup- 

 port this contention, however, as may be seen by the following : 



