No. 487] 



A NEW SPECIES OF TKI.KXOMV 



423 



No attempt was made to ascertain the nature of the tropism or 

 sense which leads to the (hscovery of host eggs by the adult para- 

 sites, but it a[){)cars tliat the attraction is as ^^reat for eni])ty e^^^' 

 shells of TfufaNfa rusiafm as for unlialchc.l i-u- of F.usrhistns 

 servus in a suitable Ma.irc of developiiu-iit I'nr Mi<-c....fiil para^iti^n. 



men the pentatonii.l e^m. batch i. UnmA, tlic adult parable 

 carefully examines it with her antenna>. if the cjr^^. arc sati.sfac- 

 tory slie sets to work industriously and oviposits in one egg after 

 the other. The process of oviposition in a single host egg recpiires 

 from two and one cpiarter to three minutes. The body of the 

 female during this o})eration is held rigidly by the legs in a position 

 nearly perpendicular to the siirface of the host egg at the point of 

 introduction of the ovi{)()sitor. The puncture may be made 

 through the egg cap or top end of the egg, or it may be through 

 the side of the egg. The latter is more frequently tlie case with 

 eggs located on the outside of the batch. 



Before leaving the egg the female scrapes it for a few seconds 

 with the tip of the ovipositor, usually moving it around the point 

 of insertion making a nearly complete circle, then reversing and 

 with a shorter radius passing aroimd to or beyond the starting 

 point, then perhaps reversing again and with a still shorter radius 

 making a nearly complete circle. Sometimes a much more irregu- 

 lar figure is traced but it is always curved for the most part, and 

 so far as observed the direction of the movement is abruptly 

 reversed from one to three times. It is difficult to imagine any 

 useful purpose of this instinctive act except to mark the para- 

 sitized egg so that it can be detected as unsuitable for further 

 attack liy parasites of its own and j)robably other species. 



Egg lai/iiif/ capacifii. The largest number of pentatomid eggs 



fenude of the species here coiisidcM-cd is 27. The total number 

 of eggs which a female para-ilc may deposit a])pcars not to be 



