756 Journal of Agricultural Research vol. xx.No. 10 



just completed. As the ovipositor is removed from the cut the female 

 squats over the freshly made opening and probably at this time deposits 

 the egg. The deposition of the egg could not be seen, but it is believed 

 that the egg does not descend through the ovipositor but that it is 

 dropped in place, leaving the body of the female through the spread bases 

 of the ovipositor, before the ovipositor is completely withdrawn. 



The following is an account of the time spent by one female in each of 

 the different steps in the laying of an egg: In scratching the surface of 

 the needle endeavoring to start the incision, she spent 2 minutes and 13 

 seconds; in working the lance and lancets into the tissue, she spent 

 22 seconds; in beginning the pocket the female, with her abdomen bent 

 and close to the needle, worked for 27 seconds; and on the remainder of 

 the cutting of the pocket, with her abdomen raised, she worked 1 minute 

 and 49 seconds. The removal of the ovipositor and the deposition of the 

 egg were accomplished in 16 seconds. 



PERIODIC APPEARANCE 



Leconte's pine sawfly appears and disappears periodically. For several 

 years this species will be very abundant; then for a few years it will 

 become rare. The cause for this periodic disappearance has not been de- 

 termined, but it seems likely that some factors other than parasitism play 

 an important role, because we have no records which give a sufficiently 

 high percentage of parasitism to lead one to believe that this is entirely 

 responsible for a great reduction of the species. Investigation of certain 

 other means of natural control has thrown no light on the subject. 



PARTHENOGENESIS 



Experiments to determine if this species can reproduce parthenogeneti- 

 cally are inconclusive. In all these experiments only unfertilized females 

 of both emergence periods of brood A were used, and although all of them 

 weie failures the information acquired is inadequate to prove that the 

 adults of this brood can not reproduce parthenogenetically. Eight ex- 

 periments were performed, six of which produced eggs while two failed 

 entirely. In two experiments conducted under especially favorable con- 

 ditions the eggs hatched but the young larvae died without molting. It 

 is thus possible to state that females of brood A of this species can and 

 will lay eggs unfertilized and that these unfertilized eggs will hatch, but 

 in no experiments have these larvae produced adults. 



HOSTS 



This species appears to have three primary or preferred hosts and 

 a quantity of secondary or possible hosts. The primary hosts as de- 

 termined by observations in the field and the nursery are: Jack pine 

 (Pinus banksiana), which was subject to attack in Vilas and Oneida 



