20 BULLETIN 251, U. S. DEPARTMENT OF AGRICULTURE. 



In addition to the beetles colonized, as given in Table III, 340 

 living specimens were shipped from the laboratory during 1912 and 

 1913. Most of these went to New Brunswick, Canada, where an in- 

 festation of the brown-tail moth exists, but a small lot was shipped 

 to the commissioner of horticulture of California for colonization in 

 that State, and another lot was forwarded to Xew Mexico, where a 

 serious outbreak of the range caterpillar (Hemileuca oliviae Ckll.) 

 exists. 



In 1914, 1,830 specimens were collected by Mr. L. S. McLaine, an 

 assistant of Dr. C. Gordon Hewitt, entomologist to the Dominion 

 of Canada, and shipped to Xew Brunswick, and 1,700 were obtained 

 by Mr. H. E. Smith and forwarded to Xew Mexico by arrangement 

 with Prof. F. M. TTebster. in charge of cereal and forage insect in- 

 vestigations in the Bureau of Entomology. 1 



METHODS OF SECURING DATA FROM FIELD COLONIES. 



In order to determine whether this species has increased in spread 

 under natural conditions, a large- amount of work has been carried 

 on each year in the field. Owing to the large size of the beetle and 

 its larvae, it is comparatively easy to make observations on this 

 species. For the first few years after liberations were made observa- 

 tions were carried on in the localities where the colonies were planted. 

 The work was taken up about the 1st of July and continued as long 

 as information could be secured in August. Effort was made to 

 determine not only whether the species had survived, but to find out 

 whether it was spreading. This work gave very gratifying results. 

 On trees which were burlapped it was possible in many cases to 

 find the beetles or their larvae feeding on gipsy-moth larvae or pupae 

 beneath the bands. The beetle larvae feed extensively on gipsy-moth 

 pupae, and it is quite easy to determine if pupae have been destroyed 

 by this means, even though the insect may not be present. As the 

 larvae of sycophanta climb trees and feed among masses of pupae, an 

 examination of these masses in midsummer usually indicates whether 

 the species is present. An additional help in this respect results from 

 the fact that these beetle larvae molt among the masses of pupae on the 

 trees, and unless there are heavy rains, which wash these molted skins 

 to the ground, it is possible, for a period of several weeks after actual 

 feeding took place, to determine whether the species has been present, 

 Uusing this information as a guide, parties of men have been em- 

 ployed each year to examine infested places in the towns outside of 

 localities in which colonization actually took place. In this way it has 

 been possible to determine the spread of the insect from year to year 



1 Results of the introduction into Xew Mexico will be set forth in detail in a report on 

 the range caterpillar investigation of this bureau. 



