| Numerous sensory hairs were located upon the ovipositor sheath of the alfalfa seed chalcid.;Chemicals from the alfalfa plant were applied to the ovipositor sheath and enclosed ovipositor. Out of 81 chemicals tested, 23 were observed to elicit activity in the ovipositor, 12 were observed to have a damping effect and 46 were neutral.;Chemicals eliciting ovipositor activity in 50 per cent or more of the chalcids were citric acid, linoleic acid, oleic acid, maltose and vitamin D2.;Chemicals found to evoke activity in the ovipositor of 20 to 49 per cent of the chalcids were folic acid, beta-carotene, coumarin, hesperetin and xanthine.;Sensory hairs were also located upon the chitinous ovipositor of B. roddi. On the posterior portion of the ovipositor were found several hairs lying in a plane perpendicular to the axis.;DL-Aspartic acid, L-histidine, DL-norvaline, DL-phenylalanine, L-proline, DL-serine, cholesterol, D-galactose, beta-glucose, niacin, DL-glyceric acid, DL-malic acid and shikimic acid elicited activity in ten to 19 per cent of the chalcids.;For ten to 20 per cent of the chalcids a slight damping effect was produced by L-asparagine, L-cysteic acid, L-glutamic acid, glycine, DL-isoleucine and fumaric acid.;Reduced responses on over 21 per cent of the chalcids were produced by DL-alpha-amino-n-butyric acid, DL-methionine, glycerol, D-(+)-zylose, biotin and diethylstilbestrol.;Activity produced by many of the organic acids may have been due to their low dissociation constants. Vitamin D2 and maltose possibly influence a portion of the complex chain of reactions which initiate ovi-position in B. roddi.;Attempts to record nerve potentials from the ovipositor via electrophysiological methods were not successful. |
