116 ANNUAIi REPOKTS OF DEPARTMENT OF AGRICULTURE. 



to introduce and acclimatizo parasites which attack the injurious 

 moths in their native homes have been carried on now for rather 

 more than five years. The work has been novel in its character 

 and entirely unprecedented in its scale, but it was initiated under 

 more favorable conditions than could have occurred elsewhere in 

 the world, on account of the intimate acquaintance possessed by 

 members of the Bureau force with parasitic insects and their habits. 



The progress made from year to year has been shown in my annual 

 reports. It was at first hoped and even expected that appreciable 

 results in the obvious lessening of the damage done would be per- 

 ceived in a very few years — say three or more — but with a better 

 understanding of European and Japanese conditions and with a 

 closer knowledge of the biology and interrelations of these very 

 minute creatures, complications have arisen which, while affording 

 new and important light, have lengthened the estimate of the Bureau 

 of the time needed to get the best results. 



During the past fiscal year a larger amount of parasitized material 

 was imported than ever before, and the thanks of the Department 

 are due to officials in Italy, France, vSpain, Portugal, Russia, and 

 Japan for assistance in this work. Some very notable examples of 

 progress have been observed. The European predatory beetle known 

 as Calosoma sycoj)lianta now exists in great numbers over a large area. 

 It was so abundant in some localities the past year as to afl'ect the 

 gipsy moth materially. A parasitic fly of the genus Compsilura, 

 first liberated in 1906, during the present season has been shown to 

 have increased fiftyfold annually and to have spread 10 or 12 miles 

 in every direction each year. It has destroyed large numbers of 

 gipsy moths and an appreciable percentage of the brown-tail cater- 

 pillars, and is now turning its attention to certain native species, 

 such as the fall webworm and the tussock moth, which, through 

 their autumn feeding, afford food for a generation of the parasites 

 at a time when the gipsy moth and the brown-tail moth are not avail- 

 able. Still another species has been found to attack the caterpillars 

 of the cabbage butterfly as well as the two species for which it was 

 imported. The European Monodontomerus, which was found last 

 year to have spread over an area of approximately 500 square miles, 

 has continued to increase and to disperse rapidly. It has crossed 

 into New Hampshire, extending its range 10 miles in every direction, 

 and must be at least twenty-five times as numerous this year as last. 

 A parasite of the eggs of the gipsy moth (Anastatus) survived the 

 winter of 1909-10 and appears to be strongly established. This para- 

 site will be of very considerable assistance, although alone it could 

 not be a very serious check to the gipsy moth, since its larvae destroy 

 only the topmost eggs in a gipsy-moth egg mass and since it wastes 

 many of its eggs. The condition of the parasite work, on the whole, 

 is distinctly more encouraging than it has hitherto appeared to be. 



