ORTALID^E INTRODUCTION. 29 



stress in this statement should be laid upon the remainder of the 

 structure, which is the same in all the genera. In the fifth place, 

 the mention of the bristles on the first longitudinal vein should 

 not be admitted in the definition of the family. 



The definition of the Ortalidse can therefore be put in the fol- 

 lowing manner : Front broad in both sexes ; on both sides of 

 the vertex a more or less developed swelling runs down the front, 

 upon which, before the bristle of the vertex, one or two erect 

 bristles are inserted, which, however, are wanting in some genera. 

 Otherwise the front has only the ordinary pubescence, or is quite 

 bare, but never provided with a second row of strong bristles 

 along the orbit, even when the hairs on both sides of the vitta 

 frontalis almost acquire, in some few genera, the character of 

 bristles. Frontal fissure distinct; frontal lunule never pushed 

 so far up as to appear to be a part of the front ; even in those 

 genera in which, on account of the great curvature of the frontal 

 fissure, as in CEdopa, the lunule happens to lie higher than the 

 antennae, it always distinctly appears as a part of the face; in 

 many genera it is not distinguishable from the face. The vibrissae 

 are always wanting. The eyes are bare. The clypeus is always 

 distinct, of various size, usually well developed. Proboscis more 

 or less stout. Palpi rather broad, often very broad, very seldom 

 narrow. Metanotum larger than usual, strongly projecting pos- 

 teriorly and inferiorly. Feet generally rather stout and short, in 

 some genera, however, of a considerable, although not striking, 

 length and slenderness. Middle tibias distinctly spurred ; front 

 and hind tibiae spurless ; no erect preapical bristle before the end 

 of the upper side of the tibiae. The abdomen of the male has 

 four segments, however the first consists of two coalescent seg- 

 ments, which is also the case in the females ; the but little 

 developed fifth segment represents a small, more or less imbedded 

 hypopygium ; the tape-like or thread-like penis is of an extra- 

 ordinary length, rolled up in a spiral. The female abdomen 

 consists of five segments, the fifth of which is often very much 

 abbreviated, sometimes wanting, so that the abdomen of the 

 female then seems to consist of only four segments ; the sixth, 

 seventh, and eighth segments of the abdomen are converted into 

 the three telescope-like, extensile joints of the ovipositor, ending 

 in a simple, hairless point ; in most cases the ovipositor is flat- 

 tened, and then its first joint often differs but little in its nature 



