10 U.S. NATIONAL MUSEUM BULLETIN 2 83 



basistyle, which, in older terminologies based on Culicoides, have been 

 called the dorsal and ventral roots of the basistyle, require special 

 terminology as explained in the generic diagnosis. 



The illustrations were made by the senior author who normally used 

 an ocular grid and squared paper; a few (i.e., thoracic patterns) were 

 freehand sketches from pinned specimens. No attempt was made to 

 preserve a uniform scale. A careful selection of parts was made to illus- 

 trate a species. Within a group, the more common or better known 

 species is selected for detailed illustration, and in other species of that 

 group, only the diagnostic aspects are figured. Thus, the interorbital 

 region, maxillary palpus, femora-tibiae, and last 2 tarsomeres and claws 

 of the female are ordinarily illustrated for only 1 species of each group. 

 Details of the male and female genitalia and the female spermathecae 

 have special taxonomic significance; for this reason, they are figured 

 whenever possible. 



Our measurements were made with an ocular micrometer on speci- 

 mens cleared in phenol and mounted on slides in balsam. The measure- 

 ments are usually presented in the descriptions in the form "mean 

 (minimum-maximum, n = number of measurements)" unless a single 

 specimen is being described. Characters with unit values such as man- 

 dible teeth and tibial spines are given as "range (average, n = number 

 of specimens counted)." 



