EGG PARASITES OF THE GIPSY MOTH. 



175 



at the time when they must be placed, if placed to advantage, more 

 could easily be collected. 



The rate of increase in the field, as indicated by the work which has 

 been done, is not excessive, but probably amounts to something like 

 sixfold per year. The extreme limit of dispersion discernible in 1909 

 was not quite half that of the extreme for two years, as indicated in 

 the diagram. It is possible that it may become more rapid as time 

 goes on, and it is rather expected that a high wind, at an opportune 

 time, will assist materially in the dispersion of the species. Should it 

 not, it will require a very long time for it to become generally estab- 

 lished everywhere through the infested area. Even though there 

 were a colony planted to each square mile, something like 16 years 

 would elapse before all of them met and fused, unless the present rate 

 of dispersion were accelerated. 



It has been pretty definitely proved of Schedius that it can only 

 attack the uppermost layer of eggs in each mass, and the same is 

 equally well proved in the case of Anastatus. Since there are two 

 layers of eggs, and usually three in all but the very smallest masses, it 

 is evident that the usefulness of Anastatus is still further reduced 

 through its physical limitations. The figures of percentages given in 

 the diagrams probably represent about the maximum which can ever 

 be expected. None the less, this means a distinct benefit, and with 

 all its faults, Anastatus stands high in favor at the present time. 



In its distribution abroad, Anastatus is, as might be expected, of 

 quite local occurrence. It has been received from about half of the 

 localities represented by the European importations, and in very 

 variable abundance. The numbers found in iiYe lots of what was 

 estimated as 1,000 egg masses each, received from five different locali- 

 ties in Hungary through Prof. Jablonowski in the winter of 1908-9, 

 is rather typical in this respect. As estimated through careful exam- 

 ination and counts, these numbers were as follows: 



Laboratory 

 Number. 



Locality. 



Number of 

 Anastatus. 



3017 



3018 



3019 



3020 



3021 





34,000 







208 



6,099 



39, 000 







Dorgos (Temes) 



Sistarobecz (Temes) 



Total 



' 79,307 





In Japan it is also unevenly distributed. The most which were 

 received from that country were in a lot of eggs from Fukuoka Ken, 

 received during the same winter as those above mentioned from Hun- 

 gary. It is not at all common from the vicinity of Tokyo, and while 

 it is present in nearly every lot of Japanese eggs which has been received, 

 in every instance but one (the shipment above mentioned) the number 



