5. ODONTOMYIA 145 



dullness caused by dense coarse punctuation ; there is a narrow middle 

 channel from the point of the vertical triangle to just before the base of the 

 antennai, and the frons bears a conspicuous short scaly orange pubescence, 

 which though scattered all over tends to form two patches on each side 

 against the eyes, one about the middle and the other at the lower outer 

 corner ; just below this last spot a channel crosses fi'om the eyes towards the 

 antennae which is smooth, bare, and shining on its upper side and sometimes 

 leaves the sides of the face below it polished and bare, and before reaching 

 the antenna? this channel spreads out above and below them and is less 

 defined ; the frons is about three times as long as the face ; face produced as 

 in the male, with a pubescence similar in texture to (though much scarcer 

 than that on the frons), and forming a patch on each eyemargin just below 

 the smooth i)art, and below this patch is a smaller smooth part ; there is 

 usually a dark ferruginous space at each side of the front of the mouth- 

 opening ; jowls with the pubescence less scaly close against the eyes, but 

 continued densely all over the black flat collar behind the eyes, and con- 

 spicuously glistening pale yellow ; all the back of the head well puffed out from 

 the' eyes, and more so on the upper half than on the lower, but there are no 

 black hairs and no fringe ; the actual back of the head is black and hollowed 

 out. Eyes with the facets all equal, but there is an inconspicuous slight 

 dark band across the eyes about their middle ; in life they are (according to 

 Dr Sharp) greenish bronze with a narrow transverse dark line and with 

 numerous irregular small dark dots, but Colonel Yerbury informs me that 

 these latter characters are often absent. Antennae reddish brown, but the last 

 two annulations of the flagellum blackish brown. 



Thorax, scutellum, and pleurae all densely covered with glistening scaly 

 short yellow or bronze pubescence which is, however, not quite dense enough 

 to obscure the black ground colour • usually a pair of rather broad black 

 stripes can be traced on the front part succeeded by a middle stripe down the 

 hinder part, but sometimes only a narrow middle line runs down the disc 

 Avith a ci'oss-line along the suture, but the cross-line does not extend inwards 

 enough to touch the middle line, and none of the lines extend to any margin. 

 Scutellum with a pair of inconspicuous dull yellow spines. 



Abdomen somewhat like that of the male, but the black marking on the 

 basal segment is narrower than that on the second segment, while that on the 

 second segment is wider than in the male and is very slightly narrowed 

 downwards, the marking on the third segment is as wide as that on the 

 fourth segment, and the combined markings of these two segments make the 

 end half of the abdomen black with a broad reddish orange (in death) margin 

 of almost equal width, as the black colour only just extends on to the fifth 

 segment at the middle. 



Legs darker orange. 



Wings, squamse, and halteres as in the male. 



Length about 7 mm. 



This species varies very considerably, and many of the varieties have 

 been given specific names. I have not met with any of the extreme 

 forms in Britain, but yet our specimens vary quite enough to cause 

 uncertainty among those who do not know the species well. The black 

 dorsal abdominal markings vary in width, being sometimes broader on 

 the second and third segments to almost half the width of the abdomen 

 and bearing outward prongs at the sides near the foremargins ; the five- 

 sided spot on the fourth and fifth segments may be larger and less 

 regular in outline or may extend almost to the hindmargin of the fifth 

 segment; the pale abdominal sides may be orange or dark green; the 

 middle femora may be considerably blackish on about the basal two- 

 thirds; and the halteres may be dark green. Two females taken by 

 Colonel Yerbury at Waterville, Co. Kerry, on July 27 and 30, 1901, 

 appear very distinct (but a normal female also occurred there on July 30) ; 

 they are slightly larger, and the abdomen has only a narrow green margin 



K 



