396 
COLEOPTERA. 
ascertained recently, the male wasp showing the pupal cocoon project¬ 
ing from its abdomen, as a brown body which on dissection proved to 
contain a dead male of Xenos. The hibernating females are also in¬ 
fested and in March, the female Xenos, in the body, yields abundant 
small active larvse which apparently pass from the queens to their 
young in the new nests. The first brood of wasps is thus infected and 
from them males have been reared. The female is a mere egg-pro¬ 
ducing sac which lives always in the wasp and is fertilised there by 
the male, which is winged. Infection occurring thus in the nest, 
there is apparently a constant succession of broods ; some wasps con¬ 
tain as many as three Xenos , which in their mature or pupal condition 
are readily visible as brown bodies attached at the junction of two 
abdominal segments, This Xenos appears to be a marked check on 
Polistes hebrceus . a large percentage being infested in some cases. 
Fig. 272.— Male of xenos from polistes 
HEBR iEUS. X 12. 
