SEQUENCE OF GIPSY-MOTH PARASITES IN ETJEOPE. 131 



as enemies of the gipsy moth. Of them all, not one refused to attack 

 and devour the caterpillars and pupae of the gipsy moth with business- 

 like dispatch, once given an opportunity, but with one or two excep- 

 tions none has shown a disposition to climb trees in search of its prey. 

 Being essentially terrestrial in habit, they were essentially unfitted 

 to prey upon an essentially arboreal insect. 



We know little of the predatory beetles which are to be found in 

 that part of France which was visited upon this occasion, nor does 

 this lack of knowledge vitiate the strength of the argument to any 

 great extent. The fact was that if present (and undoubtedly some 

 species are to be found) any of the numerous forms which have been 

 studied at the laboratory and discarded as unfit for the purposes de- 

 sired in Massachusetts would immediately assume high rank as ene- 

 mies of the gipsy moth. In other words, the conditions under which 

 the gipsy moth exists in southern France are wholly incomparable with 

 those under which it exists in New England, and the agencies which 

 are effective in accomplishing its control are likewise incomparable. 

 The unimportant role obviously played by the parasites immediately 

 loses its significance. Those species of true parasites which assist in 

 this control are practically the same as those which assist in other 

 localities, but the demand upon them and their opportunities for mul- 

 tiplication are insignificant compared to those existing in Massachu- 

 setts, if they are ever established there. True to their character as 

 agencies in facultative control, they do not increase in efficiency to an 

 extent which would practically mean the extinction of their host. 



The results of the rearing and dissection work carried on at the 

 laboratory indicated that a parasitism varying from 25 per cent to 

 something in excess of 40 per cent prevailed in this locality. After 

 seeing the conditions under which the gipsy moth struggled for ex- 

 istence, real wonder was felt that it should be able to survive, and the 

 trip resulted in a firmer conviction than ever in the efficacy of para- 

 sitism, and the validity of the theory upon which the parasite-intro- 

 duction work was conceived. 



SEQUENCE OF PARASITES OF THE GIPSY MOTH IN EUROPE. 



The parasitic fauna of the gipsy moth varies considerably in various 

 f aunal divisions of Europe, and no attempt has been made to prepare 

 separate lists of the parasites peculiar to those regions which have 

 been represented in the material imported. In Table II, which is con- 

 structed in accordance with that representing the sequence of para- 

 sites in Japan, as explained on page 122, all of the various species reared 

 from the European material are listed. As in the table of Japanese 

 parasites those species which are of no consequence in the control of 

 the moth (so far as known) are marked with an asterisk. 



