566 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol 4. 



the parasites of two introduced pests and subsidiary investigations of several native 

 species. An examination of the bulletin shows it to be an important chapter in 

 American entomology with ramifications extending to remote parts of the globe. 



The senior author, in the introduction, gives a compreheasive and moderately 

 detailed discassion of previous work in the practical handling of the natural enemies 

 of injurious insects. Much of this is familiar to working entomologists though they 

 will greatly appreciate the assemblage of this data, while for others it is almost essen- 

 tial to an understanding of the problem. The narrative detailing the progress of 

 the work shows a weU-planned development and gives an excellent idea of the com- 

 plexity of the subject and the nximber of collaborators neces.sary. The investigation 

 developed marked contrasts between the previous recorded parasites and the species 

 actually reared from imported material. We now have as an outcome of the.se 

 studies, an authentic h.st of the parasites and predaceous enemies of the gipsy and 

 brown-tail moths, though no one unfamihar with the subject has an adequate con- 

 ception of the prolonged, careful investigations involved in ascertaining the relations 

 of the various species to each other and their hosts. It was found not only neces- 

 sary to study the parasites issuing from imported material, those attacking the hosts 

 in America, but the work was wisely extended to include field observations upon 

 the natural enemies of these insects in various European countries. The latter 

 procedure proved nece.ssary to a compreheasive understanding of the situation. 

 The data secured abroad may prove invaluable when apphed to solving the problems 

 presented in America. 



The summary shows that there have been introduced into this country, two egg 

 parasites of the gipsy moth, one Hymenopterous and nine Tachinid para.sites of 

 gypsy moth caterpillars, four parasites of the pupai and one predaceous beetle. The 

 brown-tail moth has not been neglected, two egg parasites, four parasites of the 

 smaller caterpillars, six of the larger caterpillars and three of the pupse having been 

 imported. The vast amount of material handled during this investigation is shown 

 by the fact that over a miUion and a half of Hymenopterous para.sites, over 63,000 

 Tachinid parasites and over 18,000 predatory beetles were imported from foreign 

 countries. Each of the more important species, at lea.st, has been the subject of 

 careful investigations designed to ascertain all biological data which might be of 

 service in the work of introducing and e.stablishing these natural enemies. The 

 series of maps show that a number of the imported forms have already attained 

 a wide distribution, and lend much strength to the hope that in a few years the 

 parasites may be of material service. An extended dissemination may be followed 

 by rapid multiplication in the next few years with corresponding benefits. Those 

 most famihar with the work look forward to a favorable outcome of this, the largest 

 experiment in economic biology. The undertaking, while costly, is immensely 

 cheaper than an unending and uneven struggle with hordes of voracious caterpillars 

 strongly estabhshed over extensive areas and capable of subsisting upon a great 

 variety of plants 



The numerous excellent illu.strations, together with the discassions of apparatus 

 and methods, will prove of great .service to the working entomologist. The several 

 colored plates, while giving a fair idea of the characteristics of the insects dehneated, 

 do not, in our estimation, do justice to the original illustrations. Those responsible 

 for the bulletin are to be congratulated upon having produced a work of such high 

 grade and one destined to be a rehable guide for all subsequent efforts along such 

 lines. 



