48 



rsixiiE. 



[Miiy^um- iS 



ON AN EGG-PARASITE OF THE CURRANT SAW-FLY {NEMA TCTS 



VEiYTRICOSUS). 



nV JOSEPH ALHERT I.IXTNER, AI-RAXV. N. V. 



[Ro:ui before tlio Am -riccin Association for the Advancem2nt of Science, at its Montreal 



mcetins;, 29 Aii£;ust 1SS2.] 



Dr. Asn Fitch, ill iiis 1 3th Animal 

 report on tlie insects of New York for 

 the year 1S67 (Trans. N. Y. state 

 agric. soc. for 1S67, 1S6S, v. 27), p. 

 931-933, inaile the following relerence 

 to this insect : 



"As none of the 'foreign acconnts 

 which we have seen allude to anv para- 

 sitic enemy of this currant saw-Hy. it 

 seemed (juite improbable that it would 

 in this country meet with any such 

 enemy, to lighten from us the task of 

 combatting it and diminishing its devas- 

 tations. But our valued friend J. A. 

 Lintner, of Schoharie, greets us with 

 the glad tidings that he has di.scovered 

 we have such a foe to this formid- 

 able scourge. An e^g parasite of this 

 saw-fly inhabits our state, an exceedingly 

 minute hvmenopterous insect, which 

 inserts its eggs into those of the saw-fly, 

 that its young ma\- subsist upon and con- 

 sume the contents of tiiose eggs. This 

 diminutive little fly has probably existed 

 liitherlo upon the eggs of somj one of 

 our American sa<v-Hics similar in size 

 to those of the currant saw-fly ; and it 

 has now discovered that the eggs of this 

 newly arriveel foreigner are equally well 

 adapted to its wants. And so iiiulti- 

 ]5lied has this little friend of the gar- 

 dener become, that in Utica Mr. Lintner 

 lliuls that among fifty eggs of a saw-fl\' 

 upon a currant leaf, there will not be 

 more than four or five that will hatch 

 currant worms, all the rest being occu- 



pied b}' the little maggot, the young of 

 this parasite. At .Schoharie, also, where 

 the saw-fly has arrived more recently 

 than at Utica, he linds this parasite 

 is now beginning to appear. Every- 

 where this little creature is no doubt 

 following upon the tracks of the saw- 

 flVi and within a very few years after 

 the one arrives in any place the other 

 will be there also, and will speedily 

 become so multijilied as to ijuell and 

 extinguish it. This is a most impor- 

 tant discovery, and renders it quite 

 probable that in this country this cur- 

 rant worm can never be but a tempo- 

 rary evil. Whenever circumstances 

 favor it and enable it to multiply and 

 become numerous in any section of our 

 country, this little enemy, its mortal foe, 

 will speedily be there to subdue and 

 stamp it down. Thus nicely are the 

 works of nature balanced, and no crea- 

 ture is permitted to usurp a place in her 

 domain which does not belong to it." 



The specimens of the parasite obtained 

 by me, at the time referred to in the 

 above notice, were submitted to a friend 

 who had made study of the group 

 to which they belong, who believed 

 tliem to be an undescribed species, and 

 was only able to give them a doubtful 

 generic reference. Thcv were siibse- 

 (|uentl\' destroyed, and from that time 

 until the present year (an interv.il of 

 fourteen years), although 1 have con- 



