252 BULLETIN 13, UNITED STATES NATIONAL MUSEUM. 



9 . Leuo'th, G"". Size and markings of bead, thorax, and wings as in 

 T. (lequale, the legs "ochre yellow, except the shanks and feet of the 

 first pair, which are black" (Harris). Abdomen mostly yellow, first 

 segment black, an anterior fascia and a middle one moderately broad 

 on second, a very narrow interrupted black fascia on third, fourth, and 

 fifth, and the hind margins of all the segments black. The narrow 

 fascijB might be better described as pairs of narrow transverse spotvS. 

 The yellowish triangular spot in front of the scutellum is more conspic- 

 uous than in my specimens of T. aequale. 



About the present species there has been some confusion, and I am 

 not at all sure that I can definitely settle it. The three or four species 

 are very closely allied, and only a considerable amount of material will 

 enable one to determine with certainty their true relations. The differ- 

 ences only consist in the color of the femora, an additional spot on the 

 thoracic suture, and the abdominal bands. The present species is ap- 

 parently the same as the male that Osteu Sacken described in Harris' 

 Report (3rd ed., j). 609), the female of which he afterwards decided (Cat. 

 Dipt., p. 253) does not belong with it, and which I have called T. venu-s- 

 tum. The chief evidence that 1 have, however, is a specimen without 

 abdomen, kindly loaned me by Mr. S. Hetishaw, of the Boston Society 

 of Natural History, bearing the label "179 — T. W. H.,"and which, most 

 probably, was a specimen used by Harris when he made the brief de- 

 scription. This specimen has the single elongate sutural spot on each 

 side, so that it cannot be T. alternans ; the legs are, however, as he de- 

 scribed them — that is, yellow, except the front tibiae and tarsi, while 

 aequale^ according to Osten Sacken's and my own observations, always 

 has the femora more or less black. A single specimen that I have 

 from Tennessee agrees both with this and the males Osten Sacken de- 

 scribed, the abdomen being as I have described it above. Hence I 

 think that the conclusion here given is the correct one; at least we have 

 no evidence to gainsay it. That it is nothing more than a variety of 

 aequale I am not prepared to say ; in such case this name will have pre- 

 cedence. 



TemnoBtoma alternans. (Plate, XII, figs. 7, la. ) 

 Temnostoma alternana Loew, Centur., v, 37. 



Habitat. — Canada, Maine, Kew Hampshire, Connecticut, Pennsylvania 

 Massachusetts !. 



9,9. Length, 12 to 15""". Head thickly golden yellow poUinose ; the 

 vertex, a median frontal and facial stripe, and the cheeks shining black; 

 pile of the vertex black. Antennae reddish or yellow. Face gently con- 

 cave in the middle. Thorax brownish black, a little shining; the 

 humeri, a rounded spot at outer end of suture, and a smaller one toward 

 the middle, a vittula running from the post-alar callus to near the suture, 

 a triangular spot in front of the scutellum, and a large elongate spot on 

 the meso-pleurae, bright yellow, the color due to pollen, which in rubbed 



