Comparative biology of the Wyoming and Louisiana populations of Reesimermis nielseni, parasitic nematode of mosquitoes.

coverslip was mounted off-center on a 12-ram diana brass stub coated with clear fingernail polish, and the specimens were dried for scanning. A Denton DV-502 high vacuum evaporator operat ing at 3 x 10 -5 T o r r was used to spread a standard layer of gold on tlte specimens. A Jeol JSM-2 SEM with an accelerated voltage of 35 kv scanned the parasitized larvae. A light compound microscope was also used to look at the specimens. Kodak Tr i -X Ortho fihn No. 4163 was used to make the photographs. SEM showed root-knot larvae parasitized by 7-12 D. penetrans spores attached to the nematode cuticles (Fig. 1). T h e spores were rounded above and flattened below. A round cap was part of the mature spore (Fig. 2, 3). T h e spores averaged 4.3 ~m diam by 1.6 /~m in depth, and the spore cap 2.8 /~m diam by 0.4 ~m in depth. Except for the wrinkled lines at their juncture, the spore and its cap were smooth. Pressure on the cuticle probably caused the flattened spore bottom. Buds and tubes were seen on the spore hases (Fig. 3). T h e buds apparently form tubes that penetrate the host cuticle. SEM photos of buds and tubes on mature spores confirm the observations of Allen (1). Research Notes 273