48 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
in small specimens, they are not used because of their small size and 
tendency to disappear, yet in one genus (not treated) they are well 
developed. 
Abdomen. — The most striking character of the chaetotaxy of this 
body region is the presence or absence of two marginal bristles on the 
second segment. This segment sometimes bears a complete row of 
marginals, that are short, slender, and strongly reclinate. The third 
segment may have two long, stout marginals; a complete row all 
equally strong; or short, slender, strongly reclining ones between the 
larger ones at the center and the laterals. The fourth segment bears 
a complete row of bristles on its posterior margin that usually ends 
ventrally at the forward turn of the margin, but may be continued 
forward nearly to the third sternum. In species which probably be- 
long to Blaesoxipha the ventral posterior margin of the second and 
third segments bears short, slender bristles, and the marginal row of 
the fourth segment is very short, the bristles resembling prickles. 
Females. 
\Yhile this paper does not deal with females, the writer has become 
acquainted with their characters in a general way and a brief compari- 
son of the two sexes is given for the three genera presented. 
In most species the front is considerably broader than in the males 
and the inner orbits of the eyes on its upper part are parallel or even 
diverge downward. Orbital and lateral vertical bristles are regularly 
present. The vestiture of the genae, the color and character of that 
of the back of the head and cheeks, the number of rows of black cilia 
behind the eyes, and the character of the frontal bristles are usually 
the same in both sexes. In Boettcheria the hairs of the arista are 
longer in the females. 
Except that the inner presutural and apical bristles are usually 
lacking in fernales the chaetotaxy of the mesothorax is the same as in 
males, also the vestiture of the mesonotum and the color of the spiracu- 
lar hairs. The hairiness of the sides of the thorax is less dense, and 
the lower sternopleura more commonly bears bristles only. The color 
of the epaulets and usually the characters of the wings are alike in 
both sexes but the angle formed by the bend of the fourth vein is 
sometimes different. The occurrence of a submesotibial bristle i? 
possibly coincident in males and females of the same species. The 
vestiture of the legs is short and the bearded tibiae so frequently met 
with in males do not occur. The intermediate row or rows of bristles 
J 
