220 Illinois State Laboratory of Natural History. 



Zart'a.— Length 25-30 mm., diameter about 4 mm 

 This looks very much like the two preceding species, and 

 is of the same color. The pubescence is distinct and 

 dark brown; the anterior divisions show but two im- 

 pressed transverse lines; the middle fold of each posterior 

 division bears a darker low transverse ridge with four 

 seta^ above and four pairs of setse below, each pair very- 

 approximate; posterior divisions with two principal 

 lateral setae, anterior with one, thoracic segments with 

 three or four. 



Last segment quite distinct, the upper teeth rather 

 long, strongly diverging and recurved, outer pair dis- 

 tinctly shorter than inner pair, latter entirely black, 

 forming a pair of slender tapering sharp-pointed re- 

 curved hooks; outer pair with a posterior longitudinal 

 black stripe along nearly the entire length of each. Stig- 

 mata large, black, distant, separated above by the black 

 bases of the inner teeth ; lower teeth small, with a dis- 

 tinct black \-mark on their sides and apex; anal promi- 

 nence tuberculate as usual. 



Family TABANIDtE. 



The horse-fly larvae [Fig. 41, 47, 49, and 50] are very- 

 uniform in structure and appearance, and are easily 

 known by their glassy, whitish cylindrical bodies witb 

 similarly tapering ends, a retractile chitinous head in 

 front, and a retractile short breathing tube at the tip of 

 the last segment above, seemingly an additional segment. 

 The smaller species and theyoung of larger kinds are only 

 faintly marked, but the larger larvae are distinctly ringed 

 and laterally striped with dusky or blackish. They are 

 predaceous, restless, and active, and the larger examples use 

 their mandibles freely as a means of defence, readily punc- 

 turing the skin and producing a momentary sharp pain. 



Some are terrestrial, but most of the species live in 

 the wet sand, mud, or matted and drifted vegetation o^ 

 shores, where they are sometimes quite abundant, bur- 



