F. R. COLE 57 



triangular black mark. Pleura black. Venter black, with 

 brown blotches. Last segment of venter very short. Length, 4 

 mm. 



A specimen received from J. M. Aldrich was collected at Fri- 

 day Harbor, Washington, July 23, 1905. The median stripe on 

 the thorax does not reach the scutellum and the elongated oval 

 spot on each side barely reaches the praescutellar callosities; 

 upper pleura brown and yellowish. Basal brown triangles on 

 second, third and fourth abdominal segments. There are no 

 markings on lateral margins of abdomen. The halteres are yel- 

 low. Venter yellow, brownish toward tip, two round black spots 

 on second segment of ovipositor. 



This species resembles A. trigramma Loew in general appear- 

 ance, if one can depend on Loew's figure (79). A. trigramjyia was 

 described from Sicily. 



Acrocera nigrina (PI. XII, fig. 35.) 



Acrocern nigrina Westwood, Trans. Ent. Soc. London, v, p. 98, (1848). 



Head and thorax black. Thorax with short grayish-white appressed hair. 

 Humeral -callosities bright yellow, pleura black. Post-alar callosities black- 

 ish-brown, with yellow at each end; scutellum black. First two segments of 

 abdomen all black. Two large yellow spots on third segment, fourth segment 

 largely light yellow with black median basal triangle. Median black spot on 

 fifth segment; the genitaha blackish-brown. Venter blackish-brown, with 

 narrow yellow posterior margins to segments; the last three segments more 

 broadly yellow. Squamae hyahne; the halteres bright yellow. Legs yellow 

 with a pale brownish tinge, the middle section of the femora and tibiae darker. 

 Claws and most of last tarsal joint, black. Second vein usually entireh' lack- 

 ing; there may be a bas^l, rudimentary stump. Wing dark brown. Wings 

 with a pale brown tint. Length, o to .5.5 mm. 



Habitat. — The type is in the British Museum, and was de- 

 scribed from Georgia. 



Mr. C. W. Johnson noted, in his paper on the genus Acrocera, 

 that a specimen from Quebec (Provancher) had a stump of the 

 second vein, the basal end, in each wing, and also a short median 

 section of this vein in one wing (see fig. 35) and two sections in the 

 other wing. This specimen was included in material loaned by 

 the Museum of Comparative Zoology. Johnson advances the 

 theory that bnlla, biviaculata and nigrina may be varieties of one 

 species, which is not at all impossible. 



TRANS. AM. ENT. SOC, XLV. 



