WERNER MARCHAND 105 



Tabanus costalis Wiedemann. — Habitat, eastern North America. 

 The species is very common, and a pest to stock. Of its early stages 

 v/e know Kttle. There are no data available on its oviposition, and 

 although Hine (1903), while speaking of the control of tabanids in 

 Louisiana, mentions that oviposition in tabanids often takes place 

 not over water but over damp ground, and that "one finds the eggs 

 of costalis and a number of other species in such places quite fre- 

 quently," he gives no description of the eggs. 



The larva seems, according to Hart, to be normally a terrestrial 

 larva. He has found it two or three times in the earth of corn fields 

 in Champaign County, Illinois. The dates given are May 31 and 

 June 4. Specimens were placed in a breeding cage, and an imago of 

 costalis was secured from them.^'' Hart believes that the species is 

 single-brooded. His description of larva and pupa follows: 



^^ Larva. — Length 20 mm., diameter 2.7 mm. Prothorax with lateral shining 

 areas about as long as the dorsal, coarsely striate, a smooth spot near center of 

 disk; dorsal and ventral areas of thorax smooth, a few striae on those of meta- 

 thorax, especially posteriorly; remaining areas moderately striate, lateral areas 

 of abdomen a little more finely striate than the others; all more or less shining." 



"Dark annuli pale, narrow, longitudinal stripes scarcely present; false feet 

 with dull pubescent crests, their sides rather finely striate; a narrow dark annu- 

 lus at base of respiratory tube, another around base of last segment, enclosing 

 anal prominence and giving off a pair of lateral stripes, the lower one longer; no 

 projecting spine seen." 



'^ Pupa (from defective cast skin of male). — Length 20 mm., diameter 3 

 mm. Light fuscous brown, shining; abdomen smoothly wrinkled, slightly opaque; 

 prothoracic spiracular tubercles slightly but nearly equally elevated, free margin 

 rounded at tip, rima not vertical, evenly arcuate, slightly hooked in front." 



"Abdominal spiracular tubercles small, subtriangular, narrower behind, ob- 

 liquely subconical, much shorter than basal diameter, bearing a very small sub- 

 circular rima; fringes formed of unequal pale spines, the longer ones sparse on 

 seventh segment above; outer terminal teeth twice as large as lower pair, directed 

 laterally and slightly backwards; upper pair smallest, directed upwards; ventral 

 fringe of last segment not noticeably webbed; lateral tufts rather high, not near 

 ends of ventral fringe." 



Hart's material was, as he says, "not in the best condition for 

 accurate comparisons." 



^^ I have since found the larva of this species in the muddy banks of Lake 

 Carnegie in Princeton, N. J., which shows that it is not always terrestrial. 



