170 



larvfB of Uroceridae or other borers, thej" do not commonly do so. In 

 every case that he observed the ovipositor entered through wood that 

 had not been previously attacked, and in his oi)iuiou the egg is often, 

 if not generally, laid regardless of contact with the larva. He con- 

 cluded that if the Ichneumonid larvie are carnivorous they must bore in 

 search of food, as he thought it improbable that the adults perlbrmed 

 the great labor of boring oa the chance of meeting with a larva, but 

 rather that they deposit eggs at every insertion. 



In 1881: the question was brought up again by Mr. George Gade, of 

 Fordham, N. Y. who had made in'actically the same observations as Mr, 

 Clarkson, but who drew the strikingly erroneous conclusions that Tha 

 lessa is lignivorous and not i)arasitic. He is reported to have stated 

 at the meeting of the Brooklyn Entomological Society, held September 

 27, 1884 (see Bulletin Brooklyn Eutom. Soc, Vol. VII, Xov., 1884, page 

 103), that he had long doubted the parasitic habit of the species. He 

 remarked : 



I have, during tlie past season, watched many females ovipositing, and have cut off 

 the ovipositor when ready to he withdrawn, and in no Instance have I found a larva 

 of any kiud anywhere near the point reached hy the borer and where the egg was 

 deposited. The conclusion is, therefore, that the larva is a true wood-feeder, and not 

 parasitic. 



In the discussion which followed Messrs. George T>. Hulst, aud A. C. 

 Weeks are stated to have announced that they had reache<l the same 

 conclusion from independent observation. 



At the December meeting of the Entomological Society of Washington 

 we commented upon this report of Mr. Gade's observations, and later 

 wrote to the editors of the Brooklyn Bulletin a letter which was pub- 

 lished in the January (1885) number (page 123), giving the results of 

 our own observation, and quoting the following letter, which we had 

 previously written to Mr. J. A. Lintner, aud which he published in an 

 article o^ his own in the Country Gerdleman for April 17, 1884 (vol. 

 XLIX, page 331): 



I have on several occasions had opportunity of closely studying not only the mode 

 of oviposition, but of larval growtli of llhyssa. My sketches and notes are at home 

 [written from Boscawen, N. H.], but the salient facts bearing on your question I can 

 give fi'OD\ memory. In allinstauces where I have found the female depositing, it has 

 been in trees infested with Tremex columha, aud I have found her most numerous on 

 badly affected or injured trees, or even on stumps or broken trunks already partly de- 

 cayed. The instinct to reach the egg or larva of Tremex, so dwelt upon in popular 

 accounts, is imaginary. She bores directly through the outer parts of the tree, and 

 doubtless pi'obes for a burrow ; but her egg is consigned anywhere in the burrow; 

 the young larva seeks its prey, and lives and develops without penetrating the 

 body of its victim, but fastened to the exterior. This habit among parasites is much 

 more common than is generally supposed. A great many llhyssa larvas doubtless per- 

 ish without finding food, and a great many females die in probing for a burrow, 

 especially when they burrow through wood that is sound and hard. 



We also published in Science, November 28, 1884 (Vol. IV, No. 95, 

 page 486), a note making the same criticism. 



