356 



biting pests that affect cattle. The species of Tabanus attack cattle 

 and other farm animals almost exclusively, but Chrysops is a per- 

 sistent pest to human beings also, especially near rivers, lakes, or large 

 pools. At least one African species of Chrysops is responsible for the 

 conveyance of a disease affecting man, which in some respects re- 

 sembles filiariasis — a disease conveyed by mosquitoes. 



Some interesting data upon the egg-laying and other habits of 

 this family are contained in the papers listed at the end of the text 

 on the family. 



Key to Genera 



LARVAE 



1. Body club-shaped, the thoracic segments slender, the abdominal seg- 



ments robust Goniops (p. 356) . 



— Body tapered anteriorly and posteriorly, not club-shaped 2 



2. Apical antennal joint much longer than the preceding joint ; dorsum 



of thoracic segments as strongly striated as those of abdo- 

 men Chrysops (p. 357) . 



— Apical antennal joint not longer than the preceding one ; dorsum of 



thoracic segments either smooth or not as strongly striated as those 

 of abdomen Tnhanus (p. 358) . 



PUPAE 



1. One spine on each side of median line on dorsum of each abdominal 



segment much stronger than the others in the series .... Goniops. 



— The spines of each series either of an almost uniform strength, or 



at least no two spines conspicuously stronger than the others. .2 



2. Antennae projecting beyond lateral margin of head ; abdominal 



• spines uniform in length; head with 4 bristles on dorsum (PI. 

 LII, Fig. 5) Chrysops. 



— Antennae not projecting beyond lateral margin of head; abdom- 



inal spines long and short in each series ; head with 2 bristles on 

 dorsum (PI. LII, Fig. 4) Tahanus. 



Goniops Aldrich 



GENERIC CHARACTERS 



Larva. — Mandibles stout, slightly curved, apically truncated ; an- 

 tennae elongate, 3-jointed, basal joint stout, tapering apically, about 

 twice as long as apical 2 combined ; apical joint much shorter than 

 preapical; maxillary palpi 2-jointed, the apical joint slender and dis- 

 tinctly shorter than the basal. Thoracic segments very distinctly 

 tapered anteriorlv, alxlomen stout, roughly oval in outline, the whole 



