in studying the material collected by the bolivian yellow fever service between 1933 and 1942, five new species of mosquitoes were encountered (rhynchoataenia) nitens [female], psorophora (janthinosoma) circumflava [female], psorophora (janthinosoma) melanota [male], psorophora (grabhamia) dimidiata [male] and [female], and aedes (howardina) aurivittatus [female]. in addition, new evidence bearing on certain species of haemagogus has been presented and discussed. on the basis of this evidence, the validity of h. capricornii is confirmed, while h. spegazzinii brethes, formerly considered synonymous with h. equinus theob., is revalidated. h. janthinomys dyar. futhermore, is shown to be synonymous with it. illustrations are presented for the first time of the male genitalia of h. capricornii and h. uriartei, and also of a new aspect of the female genitalia of haemagogus, taking as a character the frequency of the number of setae of the ninth tergite, comparative figures for which are given. finally, notes are presented on the geographical distribution of the theree species of haemagogus considered.