Phoridae. 71 



broadly in the male than in the female; only in Phora the eyes are less 

 broadly separated and here more broadly in the female than in the 

 male. The vertex is not separated from the frons and in the descrip- 

 tions the whole space between the eyes from the vertical margin 

 above down to the antennæ is termed the frons. The frons thns 

 understood is generally broader than high, sometimes quadratic or 

 higher than, to twice as high as broad (the height measured at the 

 side along the eye-margin); the anterior margin is more or less prod- 

 uced in the middle; in many genera the frons has a fine longitudinal 

 median fiirrow; below the anterior margin the frons curves down- 

 wards and inwards and forms a large cavity, somewhat divided into 

 two, in which the antennæ are placed. On the vertex there is a more 

 or less developed ocellar triangle, bearing the three ocelli; in some 

 species (of Hypocera) the triangle, or the space on which it is placed, 

 is particularly shaped and raised, and in that case the anterior ocellus 

 may be wanting. On vertex and frons there is a number of generally 

 well developed bristles, thus on vertex two outer vertical bristles 

 near the upper eye-corners and two ocellar bristles in the middle, on 

 the ocellar triangle ; below these bristles on the frons there is a number 

 of fronto-orbital and frontal bristles; in the descriptions all these 

 bristles are for simplicity termed frontal bristles, typically they form 

 three transverse rows, each consisting of four bristles, one row at 

 vertex, one about the middle and one near the lower margin; sometimes 

 the bristles form four rows and are more than twelve in number or 

 on the contrary some bristles are wanting; besides these bristles there 

 are one or two pairs of often smaller bristles above the antennæ on 

 the anterior corner of the frons, the supraantennal bristles, they 

 may sometimes be wanting. The frontal and supraantennal bristles 

 are of the utmost importance for characterising genera and species; 

 the bristles may be very variously placed in the rows, so that the two 

 lower rows are more or less straight, or they are convex or concave; 

 the frontal bristles are reclinate, directed more or less backwards, 

 the supraantennal bristles are in a group of genera likewise reclinate 

 and then only two in number, in another group of genera they are 

 on the contrary proclinate, directed forwards and downwards and 

 there are then generally two pairs. The frontal bristles are rarely very 

 weak or almost not developed {Gymnophora). Above on the hinder 

 side of vertex there is a postvertical bristle on each side, they are of 

 moderate size, a little converging. On occiput along the posterior 

 margin of the eyes there is a row of well developed postocular bristles; 



