1982] Reed & Akre — Vespula austraica and V. acadica 191 
Figure 3. Reproductive organs of a preusurpation V austriaca. The Dufour’s 
gland (Dg) is filled with a clear oil material and was 6.5 mm long when fully extended. 
Ov= ovaries, Ps = poison sac or poison gland reservoir. 
nearly equal in overall body size, V austriaca had a wider head and 
interocular distance, longer hind tibia, and longer forewing. 
Some researchers (Beaumont 1958, Bischoff 1931, Weyrauch 
1937) stressed the robust mandible of V austriaca, while others 
(Bequaert 1916, Carpenter and Pack-Beresford 1903, Robson 1898) 
found only minor differences in size and did not consider the man- 
dible of V austriaca to be significantly larger. The mandible of V 
austriaca is definitely robust as it is wider at the base than that of the 
host. Weyrauch (1937) discussed and diagrammed the robust nature 
of the mandible of the parasite Pseudovespula ingrica (Birula [= D. 
ingrica (Birula)]. He stated that the mandible of the inquiline was 
less triangular in shape than that of the host queen; a comparison 
that was not evident in this study. Weyrauch (1937) also illustrated 
the relatively pointed fourth marginal tooth in P. ingrica. The wider 
head and genae of V austriaca and other vespine inquilines 
(Bischoff 1931, Weyrauch 1937) undoubtedly house larger mandibu- 
lar muscles. These muscles in conjunction with the stout mandibles. 
