356 



biting pests that affect cattle. The species of Tabamis 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 Tahanus (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 



GENE^RIC 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 anteriorly, abdomen stout, roughly oval in outline, the whole 



