1952] 
Feldman and Bailey — Corythucha 
103 
IV. A key to the New England species of the genus 
Corythucha Stal based upon characters of the ovipositor. 
1. Second valvulae broad, the length of either valve 2 never 
more than two and one-half times the width of their 
common base (fig. 5-9) 2 
Second valvulae elongate, the length of either valve 2 at 
least 3 times the width of their common base (figs. 
10-17) 5 
2. Common base of the second valves mushroom shaped 
(fig. 8) C. marmorata 
Not as above 3 
3. Base of second valves markedly broad, 0.31-0.35 mm. 
long, subgenital plate elliptical C. cydoniae 
Base of second valves not so broad, subgenital plate 
circular 4 
4. Second valves larger, 0.34-0.41 mm. long; first valves 
larger, 0.40-0.45 mm. long C. pruni 
Second valves smaller, 0.23-0.28 mm. long; first valves 
smaller, 0.29-0.34 mm. long . C. arcuata, C. mollicula 
5. Valve 2 extremely elongate; its length at least four times 
the width of its common base; valve 1 long, 0.53-0.61 
mm. C. ciliata 
Valve 2 never more than four times longer than its com- 
mon base 6 
6. Subgenital plate circular C. caryae 
Subgenital plate elliptical 7 
7. Distal end of valve 1 abruptly pointed C. pergandei 
Not as above 8 
8. Posterior margin of common base of valve 2 with a 
median projection, valve 2 longer, 0.52-0.54 mm. 
C. pallipes 
Posterior margin of common base of valve 2 with a 
median ridge, valve 2 shorter, 0.32-0.41 mm. . C. ulmi 
V. Conclusion 
On the basis of the characters of the female genital 
