252 The Ohio Journal of Science [Vol. XVIII, No. 7, 



The normal longevity and number of eggs a female of this 

 species can lay under natural conditions is probably greater 

 than the above records indicate. However it can be seen that 

 the adult life of the female extends throughout several weeks 

 and that the oviposition period is prolonged. Females dissected 

 show but few eggs matured in the ovaries and this fact, together 

 with the presence of all stages of the parasite in the field at a 

 given time, seem to prove this. The female generally made no 

 attempts at oviposition after two or three hoppers had been 

 parasitized. At least twenty minutes and generally over an 

 hour elapsed before the second attempt. 



An adult Deltocephalus oculatus was placed in the cage to 

 determine whether the parasite was confined to sayi as its host. 

 The hopper was seized and partly eaten without any attempt 

 at oviposition. 



The first larval stage is passed within the tissues of the host 

 and when the egg is laid externally the young larva must pen- 

 etrate into the host of its own accord. Shortly after the first 

 molt the larva begins to push its way out between the segments 

 through which the egg is laid. It molts for the first time and 

 enters the second instar four days after oviposition. Nine 

 days later larvae are found to be in the third instar which is 

 characterized by the two large head lobes. Within twenty-five 

 days after the egg is laid the larva enters into the fifth stage. 

 It issues from the sac and kills the host in from 26 to 31 days 

 after the latter has been parasitized. The mature larva is 4 mm. 

 in length, white, with no visible hairs. 



The larval sac is oval, and shining black in color, the third 

 exuvium being distinctly rugosely sculptured. The oval, white 

 cocoon is spun above the ground on the grass blades and is 

 4}/^ mm. long and 3^ mm. wide. The pupal period extends 

 from 22 to 24 days, the adult remaining in the cocoon for two 

 or three days before issuing, through an irregular hole near 

 one end. 



The species parthenogenetic, unfertilized females producing 

 females. There are two generations a year, the winter being 

 passed in the larval stage within the cocoon. The following 

 table summarizes the life history experiments. The pupal stage 

 was passed through in the green house and is included in the 

 table because the length of time under artificial conditions is 

 dentical with that of normal summer conditions. 



