•So Annals Entomological- Society of America [Vol.11, 



The 9 Lysiphlehiis is even more prolific than Toxoptera. Mr. 

 Phillips has found 9 9 with upwards of 400 eggs in their ovaries, 

 and Mr. Kelly has reared in some cases 206 individuals from a 

 single mother Lysiphlebus. The eggs are lemon shaped and white 

 in color. When excessively abundant the parasite will thrust its 

 ovipositor into old and young aphids of both sexes, including the 

 sexual 9 , even though previously parasitized ; and Mr. Phillips 

 has observed them to apparently oviposit in the dead bodies of 

 those that had been killed by fungus attack. When their num- 

 bers are not so great, they show more discrimination and seem 

 to prefer half grown individuals in whose bodies to place their 

 eggs. 



This species of Lysiphlehiis is parthenogenetic, as was first 

 ■observed by Mr. Phillips at Richmond, Indiana, and afterwards 

 more fully elucidated by Messrs. Kelly and Urbahns at Welling- 

 ton, Kansas. The experimental breedings of Mr. Phillips in 1907 

 indicated that the offspring of virgin ? Lysiphlebus were always 

 exclusively d" d" . In a series of upwards of eighty breeding 

 experiments carried on indoors, in 1908^ b}^ Kelly and Urbahns, 

 only forty-eight gave results of any kind. Of these only four 

 gave 9 9, the other giving only dd. In the four exceptional 

 cases the 9 9 kept virgin, ran all to d d, two with the first 

 generation, one with the second and one with the third. The 

 mode of procedure was as follows : 



Starting with a mated 9 , the 9 9 from among her offspring 

 were isolated, even before emergence; on their appearance these 

 were given Toxoptera reared under cover to preclude parasitism; 

 the few 9 9 from among this second generation were again iso- 

 lated in the same manner, the 9 9 in all cases being kept un- 

 mated. It was thus found possible to breed a limited number 

 -of 9 9 parthenogenetically to and including the third generation. 

 Beyond this all oft'spring were d d , this seemingly being the 

 limit. Just why such a large percentage of these experiments 

 should have proven abortive is not clear. The conditions under 

 which they were carried out were of course unnatural but much 

 more protected from the adverse elements of the open field. 



The egg of the Lysiphlebus normally develops to the emerging 



.adult in about ten days, during the first six of which the host 



insect remains alive, and at the end of that period commences to 



take on a yellowish hue, the larvae of the parasite showing clearly 



through the skin of the abdomen (fig. 8). 



