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Show 134 ME. E. E. AUSTEN ON NEW DIPTEEOUS INSECTS. [Jan. 17, (Biol. Centr.-Amer., Diptera, iii. 38), from Mexico, and Ocyptamus (Pipiza) cosfalis, Walker (Linn. Trans, xvii. 342, 31) from S. America ; it is, however, distinguished from both by its yellow face and legs, and by the colour of its abdomen, as also by its abdomen not being clothed with white, short, curved hairs, by the wings being without a brown fore-border, by the third longitudinal vein being straight, and by its smaller size. Pipiza costalis, Walker, Linn. Trans, xvii. 342, from S. America, is an Ocyptamus, allied to 0. cceruleus (Baccha ccerulea), Will., Biol. Centr.-Amer., Diptera, vol. iii. p. 38. Pipiza pica, Wlk., Tr. Ent. Soc. n. ser. iv. 156, from the Valley of the Amazon, = Ocyptamus (Syrphus) trigonus, Wied. Pipiza clolosa, Wlk., loc. cit., from the Valley of the Amazon, Ocyptamus dimidiatus, P. ( c? )• Pipiza divisa, Wlk., loc. cit., from Vera Cruz, = Ocyptamus dimidiatus, P. ( § ). Syrphus stolo, Wlk., Dipt. Saunders. 241, from Brazil, is an Ocyptamus. The type is headless. The wings are apparently precisely similar to those of the o* of 0. dimidiatus, F.; but the specimen is distinguished from this species by the yellowish markings on the sides of the abdominal segments, as well as by the yellower colour of the first two pairs of legs. /Syrphus antiphaies, Wlk., List Dipt. iii. 589, is an Ocyptamus. Syrphus peas, Wlk., loc. cit. 590, from ? = Ocyptamus fuscipennis, Say.-The head of Walker's type, as described by hitn, has been stuck on, and does not belong to it. Syrphus amissas, Wlk., List Dipt. iii. 589, from Georgia, = Ocyptamus fuscipennis, Say. Syrphus radaca, Wlk., List Dipt. iii. 590, from Florida, = Ocyptamus fuscipennis, Say, var. fuscipennis, Macq. Walker's description is drawn from two $ specimens, and not from a o*, as stated by him. The synonymy of the tw?o last-mentioned species has already been recognized by Williston, Synopsis, &c, p. 119. Syrphus iridipennis, Wlk. Linn. Trans, xvii. 345, from S. America, is an Ocyptamus, closely allied to Ocyptamus funebris, Macq. It may, indeed, be only a variety of the latter species, though the semi-hyaline space beneath the apex of the wing in the latter is much more indistinct in Walker's species, in which, again, there is a semi-hyaline streak in the middle of the submarginal, first posterior, and discal cells. The wings of Walker's type are, moreover, slightly narrower than those of specimens of 0. funebris, Macq., in the collection. Syrphus tarsalis, Wlk., Linn. Trans, xvii. 345, from S. America, is an Ocyptamus. There is a narrow pale yellow stripe on each side of the third abdominal segment, starting from the anterior angle and extending a little'more than half the length of the segment, and a mark of the same colour shaped like an isosceles triangle on each side of the fourth segment, extending from the anterior angle not quite to the middle of the segment. The |