Some Ectoparasites in the South African Museum. 295 



stigma. The 6th-7th bear 2 median hairs, 1 before the stigma 

 and 1 immediately below, i.e. 6 in all. 



The 8th tergite bears 6 hairs (3, 3) above the emergence of the 

 genitalia. The 9th tergite bears at the sides 2 patches of minute 

 bristles. 



On the under surface the segmental bands are sharply limited 

 and do not join the laterals. The 1st sternite bears 4 hairs, 

 2nd st. -5th st. bear 6 hairs, 6th st. bears 4, 7th st. bears 2, and there 

 are a few terminal hairs on the indistinct genital mark. The genitalia 

 are large and peculiar. The paramera are broadly curved near 

 their origin and again at the apex, so that the exserted apparatus 

 is lyre-shaped. The first upper pair of appendages are here broad, 

 leaf-like structures with underneath 2 strong chitinous rods. The 

 homology of these rods is uncertain, and there is unfortunately not 

 enough material to permit of dissection. The genital mark is very 

 similar to that of M. diiiinrjilni. 



$ The main differences between the sexes are to be found in the 

 head. M. heteracanthus, like M. diinorplia, is distinctly dimorphic. 

 The occipital bands are sharply defined. They are curved toivards 

 one another, and not outwardly, as they run forward. Anteriorly 

 each fuses with the ocular and antennal bands. The transverse band 

 connecting the antennae in the 3 is medianly incomplete in the 9 . 

 Thus the apex of the signature is clearly seen. Antennae simple, 

 trabeculae as long as the swollen 1st joint. For details see table. 



In neither sex do the legs call for remark. They are moderately 

 stout and Docophoroid in structure, but the large coxae of the 

 show rather a Lipeuroid feature. 



Measurements of MACKAYIA HETEEACANTHUS in mm. 



Length. Breadth. Length. Breadth. 



Head "500 -457 '542 -442 



Prothorax "135 -335 -128 -342 



Metathorax -185 -464 -185 -485 



Abdomen "9U7 -928 



Segment 1 -40 -457 



Segment 4 -57 -685 



Total ... 1-727 1-783 



1 -14 -063 -063 -05 



2 -07 -036 -05 -03 



Antennae' 3 '03 '073 -026 -026 



4 -02 -028 -026 -023 



,5 -036 -026 -035 -021 



Length of Antennae "3 '2 



