OF WASHINGTON. 13 



THE EGG-LAYING FORM. 



Early in October winged males and egg-laying females 

 appeared on blue-grass in the vicinity of Richmond, Ind. 

 They were still abroad the nth of December. Numbers were 

 dissected and found to contain from 3 to 5 eggs. In Decem- 

 ber, while dissecting females breeding on blue-grass in an out- 

 of-door cage, an individual was found containing 2 embryonic 

 larvae and 2 perfectly developed eggs. This is the second 

 time this singular phenomenon has come under my observation. 



BIRTH OF YOUNG. 



Observations were made on the manner of birth of the 

 young. Adult Toxoptera were taken from out of doors into 

 a warm room and watched under a compound microscope. 

 The young appeared to be enclosed in a delicate, membranous 

 sac, from which they would free themselves, as a rule, before 

 being dropped from the body of the mother. In several 

 instances, however, they were dropped before having ruptured 

 the sac at any point. In the latter case, they looked like 

 perfectly developed pupae before emerging from their cases. 

 When dropped in this manner they seemed to expand and 

 contract gently until the sac ruptured at the cephalic extremity. 

 By this gentle expansion and contraction they would finally 

 free themselves, leaving the sac crumpled and folded upon 

 itself. 



PARTHENOGENESIS OF LYSIPHLEBUS TRITICI. 



From observations made at intervals during the summer 

 it appeared that these parasites were parthenogenetic. In No- 

 vember experiments were begun in proving this point. These 

 observations were made indoors at a temperature of 50 F. 

 to 60 F. Seven virgin females were secured, each for a 

 separate experiment, and placed in separate cages with Tox- 

 optera known to be unparasitized. Each of the parasites 

 began ovipositing in the Toxoptera in a few minutes. After 

 one of the virgin females had ceased ovipositing in the Tox- 

 optera she was removed from that cage and confined with a 

 male, allowed to mate, and then transferred to another cage 

 containing unparasitized Toxoptera. She soon began ovi- 

 positing in them. All these parent parasites were preserved. 



Viviparous Toxoptera were used in the preceding experi- 

 ment. Lysiphlebus, however, parasitizes the oviparous indi- 

 viduals also. 



December 8, adult parasites issued from all the parasitized 

 Toxoptera. Offspring of virgin females were males ; off- 

 spring from the fertile female had predominance of females. 



