ON A PARASITIC DROSOPHILA FROM TRINIDAD. 159 



Dr. Keilin, who made a mount of them with especial reference to the genitalia. As 

 far as can be judged, they are fairly typical females, with absolutely no sign of the 

 external appendages found in the first species. There is evidence of paired and 

 unpaired chitinous processes in the mount, but they are all internal. Hence the 

 matter must, for the present, be left in abeyance pending further investigation on 

 several forms. 



The description of the Trinidad species is as follows : — 



Drosophila paradoxa, sp. nov. (fig. 2). 



A minute species, well under 2 mm. in length, exhibiting broadly the usual 

 appearance of the small pale yellow species, except for having darkened wings. The 

 whole insect is pale yellow, including the legs, except for a slight darkening of the 

 tip of the abdomen. 



Fig. 2. Drosophila paradoxa, Lamb, sp. n., X 30. 



<J. Head (fig. 3) : frons all shining, the central triangular area (bounded by the 

 dotted lines in fig. 2) being slightly depressed, with three pairs of small converging 

 hairs on the boundary lines. The chaetotaxy is quite normal, as figured ; the 

 small front bristle of the outer f.o. row is just in the same line with the large inner 

 f.o. (the position of this small f.o. bristle is a useful character in the genus). The 

 bristles are all somewhat exceptionally stout and are golden brown in colour ; the 

 ocelli are bright red. The eyes are well rounded, as shown in fig. 3 ; under a power 

 of 40 diameters a very sparse and scattered pubescence can be seen. The concave 

 hind head is also entirely yellow. The antennae (fig. 3) have the first joint quite 

 hidden by the lunular ridge ; the second joint is globular and has a few bristles, 

 an especially long one at the base, and another towards the front ; the third joint 

 is rounded in profile, but somewhat pointed when viewed from in front. It will be 

 seen that the antennae are absolutely approximated at the base, there being no 

 vestige of the facial keel so common in these small yellow species, and indeed the 



