Monophlebince. 431 



examples only. Many of the species are known only from one or the other 

 sex. The total number of species described (or semi-described) attributed to 

 the seven proposed genera is thirty-six — all told. I anticipate that, with 

 increased knowledge, this small number even will be reduced : firstly, by the 

 correct pairing of males and females (at present figuring under distinct specific 

 names) ; and, secondly, by the reduction of others to the rank of synonyms. 

 Under these circumstances I prefer to regard them all as members of the 

 genus Monophlebus^ for which I would propose the following wider diagnosis : 



Adult females large, corpulent, fleshy, usually ovoid, segments well defined ; 

 active in all stages, naked or farinose, sometimes concealed beneath loose 

 woolly or flocculent secretion, but not exhibiting definite waxy plates or pro- 

 cesses. Antennas with from seven to eleven joints. Eyes densely chitinized. 

 Legs stout, usually dark-coloured. Derm pilose, with numerous small circular 

 compound pores, setre not collared at the base. 



Adult males relatively large. Wings ample, dusky, exhibiting two strong 

 nervures and two hyaline folds; membrane corrugated. Halteres spathulate, 

 Avith an apical row of stout hooked bristles. Antennre ten-jointed, the basal 

 two joints simple, the remaining eight joints more or less distinctly tri-nodose, 

 each node with a whorl of long hairs. Abdomen with from two to ten fleshy, 

 pilose appendages. Eyes large, prominent, moruliform. Ocelli relatively small, 

 one at the hinder edge of each eye. 



The species are mostly confined to the Tropical Regions, but one {serra- 

 iulcc) is found in the Mediterranean Region. I record four species from 

 Ceylon — one known only by females, and three by males only. It is probable 

 that one of these males should be paired with the female ; but, at present, I 

 have no clue to the correct association. The species represented by females 

 only is referable to cofitrahens of Walker. The three males may be distin- 

 guished by the following characters : 



A. Abdomen with a single pair of caudal appendages furcatus. 



B. Abdomen with two pairs of appendages. 



a. Thorax yellow and black ; tarsi strongly bowed, hal- 

 teres with four bristles variegatiis. 



b. Thorax red and black ; tarsi relatively straight ; 



halteres with five bristles qiiadricandatus. 



MONOPHLEBUS CONTRAHENS, Walk. 



(Plate CLXXVI.) 



Drosk/ia contrahcns, Walk., Cat. Br. Mtts. Horn., Vol. IV., Suppl. p. 306 (1858). 



Adult female {figs, i, 2, 3) ovate, rounded in front and behind ; convex 

 above, tumescent below, the segments well defined ; dorsum with two con- 

 centric sulci dividing it into median, submedian, and marginal areas. Colour 

 dull pinkish purple, thinly but closely covered with a fine whitish mealy powder. 

 A specimen, kept in confinement, produced a few straggling irregular white 



