464 



The National Geographic Magazine 



Photo from A. H. Kirkland 



Female Brown-tail Moths Laying Eggs 

 on Cherry 



Reading, Mass., July 17, 1905 



the omission of an appropriation for sev- 

 eral years enabled them to spread again, 

 and the last several years they have been 

 more destructive than ever. Recently it 



was recognized that some method in ad- 

 dition to destroying the nests and cater- 

 pillars must be devised to exterminate the 

 moths, and a parasitic enemy of the moths 

 has consequently been imported from Eu- 

 rope. 



The gypsy moth is seen in many sec- 

 tions of Europe, but its ravages are com- 

 paratively mild because of the existence 

 of a four-winged fly which lays its eggs 

 in the gypsy moth caterpillar. To secure 

 this, fly-infected caterpillars are imported. 

 The United States Department of Agri- 

 culture, acting in cooperation with the 

 gypsy moth service of the State of Massa- 

 chusetts, has organized a service in Eu- 

 rope whose business it is to collect the 

 gypsy and brown-tail nests and ship them 

 to America. During the past season 

 116,000 moth nests were imported into 

 this country. These nests were kept in 

 sealed cages until the caterpillars de- 

 veloped, and the expert knew what was 

 to come out of the nest. Each caterpillar 

 was then carefully examined, and all 

 caterpillars found to be free of the para- 

 site were destroyed, whereas the cater- 

 pillars that contained the parasite were 

 distributed in those parts of Massachu- 

 setts where the gypsy moth is most preva- 

 lent. As each nest contained about 250 

 caterpillars, the work involved the exam- 

 ination of over 25,000,000 caterpillars, 

 and of these one-half of one per cent, or 

 about 100,000, were found to contain the 

 parasite. (It is interesting to note that 

 many caterpillars contained parasites other 

 than the desired variety ; 52 different spe- 

 cies of parasites were in fact discovered 

 and destroyed.) The parasite fly breeds 

 much more rapidly than the moth, two to 

 three weeks being sufficient for its full 

 development. The work of introducing 

 the caterpillars is under the direction of 

 Dr L. O. Howard, Entomologist of the 

 Department, who is acting in cooperation 

 with Dr A. H. Kirkland, Superintendent 

 of the Gypsy Moth Service of Massachu- 

 setts. 



