1941] 
Habits of Eucharidae 
63 
but without noticeable feeding, until its first molt, when 
they disappear. One young larva collected in the field 
carried 53 planidia upon its body, yet did not seem to be 
inconvenienced thereby. These thrips are not attended by 
ants nor is the host of the parasite known, so the significance 
of this relationship cannot yet be determined. 
Stage of the Host Which Is Attacked 
Because of the habits of the planidia, which are carried 
into the nests by the adult ants, it is assumed that that 
transfer is effected mainly, if not entirely, to the ant larvse 
rather than to the pupse. This would seem to be obliga- 
tory in attack upon hosts which pupate in cocoons. In all 
species which have been studied the parasite planidia have 
been found upon the larvse, even though development may 
not take place upon this stage. The majority of species 
permit the host to attain the perfect pupal form before 
death. Wheeler found that feeding by the larvse of Orasema 
was upon the prepupse and that the host never attained the 
typical pupal form. He designates the deformed host pupse, 
with reduced heads and appendages, as phthisergates, while 
depleted semipupse of females and males, such as result from 
attack of Orasema upon Pheidole instabilis , are designated 
as phthisogynes and phthisaners, respectively. The abstrac- 
tion of a portion of the body fluids has halted the develop- 
ment of these individuals and they eventually die. Schiza- 
spidia convergens also kills its host in the prepupal stage 
and the antennal sheaths never extend beyond the middle of 
the thorax. 
There are a number of variations in habit of the imma- 
ture stages of the species which develop ectoparasitically. 
These relate to the position of the larva on the host body, 
the stage of its development at the time of transfer to the 
host prepupa, and the time at which death of the host takes 
place. After the planidia reach the host larvse in the nest 
they attach themselves within a relatively limited area on 
the body. Those of Kapala terminalis are invariably found 
laterally on the throat, while Stilbula tenuicornis and Schiza- 
spidia are found there or in one of the sutures between the 
thoracic segments. Occasional individuals attach them- 
selves to the abdomen. 
