Fig. 309.—Trichostrongylus instabilis: left, posterior end of male; right, spicule and gubernaculum, side view. Cf. fig. 311. Magnified. (After Looss.)
Fig. 310.—Trichostrongylus instabilis: posterior end of female. Magnified. (After Looss.)
Trichostrongylus instabilis,[312] Railliet, 1893.
Syn.: Strongylus instabilis, Railliet, 1893; Strongylus subtilis, Looss, 1895.
Male 4 to 5·5 mm. long, 0·08 mm. thick in front of bursa. Spicule 0·135 to 0·145 mm. long, accessory piece (gubernaculum) 0·07 mm. thick. Antero-external ray usually thickest of all, occasionally only as thick as the antero-median; postero-median far more slender than the antero-external and antero-median and nearer to the postero-external than to the antero-median. Female 5 to 6 mm. long, vulva 1·05 to 1·2 mm. distant from the tip of the tail, placed longitudinally, 50 µ to 55 µ long, always shorter than the unpaired portion of the canal formed by the union of the two ovejectors; anus 0·055 to 0·07 mm. distant from tip of the tail; ova 73 µ to 80 µ by 40 µ to 43 µ.
This species lives in the duodenum, exceptionally also in the stomach of Ovis aries, O. laticauda, Antilope dorcas, Camelus dromedarius (Egypt), Cynocephalus hamadryas (North Africa), sheep and goats (France), and has been found by Looss in bodies of fellaheen at Alexandria and in the stomach of a Japanese female by Ijima.
Trichostrongylus probolurus, Railliet, 1896.
Syn.: Strongylus probolurus, Railliet, 1896.