530 REPORT OP THE COMMISSIONER OF AGRICULTURE. 

 TRUE PARASITES OF THE WEB-WORM. 



Up to the present time no parasites of this insect have ever been re- 

 corded. On August 18,1883, we bred a number of egg-parasites from a 

 batch of eggs found upon a willow leaf at Washington, but unfortu- 

 nately no description was made of them at the time, and, as they be- 

 longed to the soft-bodied genus Trichogramma, the specimens have 

 now become so much shriveled and altered that they are unlit for de- 

 scriptive purposes. We noticed after our return from Europe in Sep- 

 tember of this year that, at a number of points in New England, the 

 worms were quite commonly attacked by parasites, and careful in- 

 vestigation at Washington by Mr. Lugger showed the presence of no 

 less than five distinct species of primary jjarasites in addition to the 

 Trichogramma just mentioned. These will be considered in some 

 detail. The first was a new egg-parasite, which we have named Tele- 

 nomus hifidus; the others were all parasitic on the larvae, and con- 

 sisted of a Braconid (Meteoriis hyphantricE n. sp.); a Microgaster 

 [Apanteles hypliantrice, n. sp.); an Ophionid {Limneria pallipes 

 Prov.), and a Tachinid, which, though probably new, we shall not 

 attempt to describe. These last four have been mentioned in about 

 the order of their relative abundance and consequent importance. 

 An astonishing number of Web-worms were killed by the four para- 

 sites, and so many died from this cause and from the fungus disease 

 previously mentioned as to fully warrant the prediction of almost 

 complete immunity for the summer of 1887. 



In addition to these parasites found last Fall, the note-books of the 

 Division show a prior breeding of another primary parasite, which 

 will not be treated in detail here on account of insufficient material. 

 It is an external feeder on the larva and belongs to the genus Eu- 

 plectriis. It is closely related to E. platyhypence, described by Mr. 

 Howard in Bulletin o of this Division. 



We have found, however, that three of these primary parasites of 

 the Web-worm, viz, the Apanteles, the Limneria, and the Meteoyms,. 

 were killed off at a serious rate late in the season by secondary para- 

 sites, most of which belong to the family Chalcididce with the ex- 

 ception of three species of the Ichneumonid genus Hemiteles. So 

 extensive has been this killing off of the primary parasites by the sec- 

 ondary, that were not the fates of the three classes, viz, the plant- 

 feeder, the primary and the secondary parasites so interwoven, the 

 destruction of these beneficial insects might be considered a serious 

 matter in dealing with the plant-feeder. 



We have not taken time to determine these secondary parasites 

 specifically, but give a little table showing the number of species con- 

 cerned, mentioning them only by their genera: 



SECONDARY PARASITES. 



On Apanteles: 



1. Hemiteles sp. 



2. Elasmus sp. 



3. Eupelmus sp. 



4. Panstenon sp. 



5. Cirrospilus sp. 



6. Pteromalus sp. 



7. Pteromalus sp. 



