324 PERCY SLADEN TRUST EXPEDITION 



Allotrichoma, Becker. 



Allotrichoma Becker, Dipterolog. Studien, iv., Berlin. Ent. Zeitschr., xl. (1895), p. 121. 



Some 14 specimens of an insect were collected which seems to be best placed in this 

 genus. The male agrees with Becker's generic characters and possesses peculiar genitalia 

 like those figured by him {I.e., Plate IV, figs. 7, 8). The female is extremely like a Disco- 

 cerma and in both sexes the form and colour bear a strong resemblance to those of a 

 member of that genus. 



26. Allotrichoma argentiprcBtexta, n. sp. 



Shining black like a Discocerina, covered with fine sparse golden pollination. 



Head (PI. 15, fig. 20). Vertex and frons shining black, no well-marked frontal 

 triangle, in good specimens the pollination is evident. Face rather silvery, with a well- 

 marked silvery line above the mouth extending round the lower eye-margin ; prelabrum 

 exserted, shining blackish. 



Antennae black, arista thickened at the base with four side rays, shortening from the 

 base to the tip, and one terminal ray ; a well-marked bristle on the second joint. 



Fig. 15. Allotrichoma argentiprcetexta, n. sp., wing. 



Face with two well-marked side bristles; the usual cheetotaxy, backward and forward 

 orbital pair, ocellars, inner and outer verticals, strong forwardly directed post-verticals as 

 strong as the ocellars. 



Thorax with fine achrostical and other similar fine bristles each side of them on the 

 dorsum. Scutellum rounded and slightly arched with four bristles. 



Wings as Fig. 15 with dark veins. 



Halters white. 



Legs dark brown with the first joints of the tarsi light brownish yellow, last joints 

 slightly suffused. 



Abdomen $. Third segment about twice as long as the second ; fourth pointed, 

 nearly as long as the previous two ; fifth very tiny or drawn beneath. Hypopygium with 

 appendages shaped like small pale flattened strips of nearly uniform width, not spatulate 

 as shown in Becker's paper (I.e. Plate IV, fig. 7), two stout divergent hairs on the end 

 and a finer central hair, and a few various sized hairs along the side. 



$. Five segments visible, each a little longer than the previous, the fourth greater 

 than third and third greater than second ; rounded visible fifth segment, abdomen covered 

 with fine hairs. 



