58 
Psyche 
[June-Sept. 
Wheeler and Wheeler, in 1987, compiled the records of 
host preferences published up to that date, and their list 
comprises 31 species, of 15 genera. The questionable generic 
assignment of many species makes it difficult to summarize 
generic preferences, but 4 species of Orasema are recorded 
only from Pheidole, 1 from Solenopsis, 1 from both these 
genera, and 1 from Wasmannia. Eucharis has been reared 
from Messor, Cataglyphis, Myrmecia, and Formica. Three 
species of Stilbula are known to parasitize Camponotus, 
while species of Chalcura, Kapala, and Rhipipallus have been 
reared from several subspecies of Odontomachus hxmatodes. 
Considering that the larval and pupal stages of most of the 
castes of the different species of ants known to be parasit- 
ized by Eucharidse are usually of sufficient size to bring the 
parasites to maturity, we might assume that they will all 
be subject to attack. The available evidence, however, indi- 
cates that in some species certain castes are exempt, and 
these are not the same among different species. Wheeler 
(1907) states that only the soldiers, males, and females of 
Pheidole instabilis Emery are parasitized by Orasema, as 
the workers are too small to provide sufficient food for the 
larvae of the parasite. He also indicates that the single 
worker form of Solenopsis validiuscula Emery is immune to 
attack by O. coloradenis Wheeler for the same reason. 
In his studies on Stilbula cyniformis Rossi, Parker (1932) 
noted that attack was limited to the large-headed wingless 
workers and to the winged forms of the same size, which are 
presumed to be the males. 
An examination of the immature stages found in the nest 
of Odontamachus hxmatodes in the Botanical Garden at 
Peradeniya, Ceylon, indicated that only the slender, small- 
headed pupae were parasitized by Chalcura deprivata, where- 
as Schizaspidia convergens developed also upon the pupae of 
the larger workers having very large heads and long and 
heavy mandibles. These latter comprised a large portion 
of the host population. 
Sufficient information is not yet available to explain the 
above limitations of eucharid attack to certain host castes. 
Even in Solenopsis validiuscula, mentioned above, where 
size is assumed to be the determining factor, some other 
cause may well be responsible. It is known that many para- 
