150 ERNEST A. BACK. 



SECONDARY SEXUAL CHARACTERS. 



Striking examples of secondary sexual characters in the 

 form of beautifying pile and bristles appear in male of the 

 genera Ablautus, Cyrtopogon, and Heteropogon. So far as is 

 known, the fore tarsi of all the males belonging to Ablautus 

 are clothed above with short appressed white pile and on the 

 sides with longer black bristles. The males of several species 

 of Cyrtopogon and Heteropogon, in addition to similar pile upon 

 their fore tarsi, possess brushes on their middle legs. In 

 Cyrtopogon, this brush (PI. VIII, fig. 1) is formed of black 

 bristles arranged on the last two tarsal segments; in Hetero- 

 pogon, of black and white bristles on the anterior side of the 

 tibiae above the middle (PI. X, fig. 5). The same males of 

 Heteropogon are still further distinguished by a patch of black 

 bristles in the anterior side of the middle femora. 



SEXUAL COLORATION. 

 Difference in coloration between the sexes is not very 

 general among species included in this paper. In Saropogon 

 where the male is black, the female shows a decided tendency 

 toward reddish. In the cases of Saropogon combustus Loew, 

 and abbreviatus Johnson, this difference leads to the creation 

 of new species for the female. The females of Dizonias are 

 strikingly different in coloration from their males, in that 

 they are reddish with golden abdominal bands, while the 

 males, varying from black to black and red, have white 

 pruinose abdominal bands. The male of Deromyia discolor 

 Loew is black, the female reddish yellow. In some species 

 in which the male has spotted wings as Cyrtopogon bimacula 

 Walker, the female does not possess these spots, or at the 

 most, only traces of them. Females, whose males possess 

 wings tinged with milky whiteness, either throughout, as 

 Microsylum galactodes Loew, or in the anal angle, as Steno- 

 pogon California Walker and Dioctria albius Walker, have 

 wings showing no trace of this color. 



