1982] Reed & Akre — Vespula austraiea and V. aeadiea 187 
Figure 1. Front legs of a V. austriaca parasite (left) and V. acadica queen (right). 
The femur of the parasite is thicker and longer than that of the host queen. The black 
line indicates 1 mm. 
The terga and sterna of the gaster of the parasite are more diffi- 
cult to dissect apart than those of the host. This “tough armature” is 
often mentioned in regard to vespine parasites. The gastral sclerites 
appear to overlap very tightly which undoubtedly prevents sting 
penetration during usurpation attempts. However, the close fitting 
of the abdominal segments does not appear to be due to a reduction 
of intersegmental membranes or because of more sclerotization. 
Instead, V. austriaea has better developed muscles (i.e., larger bun- 
dles) in the abdominal sterna and terga than are present in the same 
segments of a V. acadica queen. For example, the three pairs of 
intersternal retractors (Duncan 1939) of a fat-laden, fall parasite are 
about 1.5 times as wide as these same muscles in a fall V acadica 
queen. Consequently, this parasite should be able to retract the 
gastral sclerites more tightly than a host queen. 
The stout, recurved sting of vespine parasites is one of the most 
important morphological adaptation to their mode of life. The two 
North American vespine inquilines, V austriaca and Dolichoves- 
