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[Vol. 89 
Table 1. Measurements of seven external body parts of V. acadica queens (N = 57) 
and V. austriaca females (N = 44). 
Mean and standard deviation (mm) 
Body part 
V austriaca 
V. acadica 
Head width** 
4.31 ±0.14 
4.09 ± 0.09 
Interocular distance** 
1.90 ±0.08 
1.78 ±0.06 
Mesonotum 
width 
4.91 ±0.19 
4.86 ±0.19 
length** 
3.80 ±0.17 
3.67 ±0.19 
Hind tibia 
length** 
3.91 ±0.16 
3.45 ±0.16 
Forewing 
length** 
13.6 ±0.50 
13.0 ±0.56 
Gastral tergum I 
width 
4.48 ± 0.20 
4.39 ±0.19 
length** 
1.70 ±0.11 
1.41 ±0.1 1 
Front femur 
width** 
0.89 ±0.07 
0.81 ±0.06 
length** 
3.16 ± 0.10 
2.78 ±0.10 
**Means are significantly different using the t test at 0.01 level of significance. 
The mandibles of both species are roughly triangular when view- 
ing the mesal (inner) face. The dimensions of the three sides are 
approximately the same in each species; however, the mandible of 
the parasite is more robust, especially at its base. This stoutness is 
apparent when viewing the ventral edge of the mandible. The 
ventro-basal area is distinctly wider in V austriaca, and the mesal 
face lacks the concavity that is typical of the mandibles of the host 
queen. The mandibles of both species have three primary or margi- 
nal teeth along the truncated, cutting margin with two alternating, 
secondary teeth and a molar shelf behind the margin as is character- 
istic of vespines (Duncan 1979). Most yellowjackets (including V 
acadica) also have a rounded projection immediately beyond the 
notch on the cutting margin (see Fig. 6 in Landolt and Akre 1979, 
Duncan 1939); however, this projection in V austriaca is pointed 
and more tooth-like. Thus, the parasite actually has a fourth margi- 
nal tooth near the dorsal edge. 
