194 Mr. G. J. Arrow on 
Waterh., while the greater development of the head and the 
fissure in is apical segment of the abdomen, in addition to 
the absence of ova, seemed certainly to point to it as the male 
of that form. The last specimen, of a much narrower shape, 
had a less developed clypeus, a different claw-structure, and 
no trace of the abdominal fissure, and upon dissection it alone 
proved to contain a genital organ of the normal male type. 
It was an isolated form not previously described, and for it 
I saw no alternative but to constitute a new genus. 
‘The examination of additional specimens, however, showed 
this to be a case in which reasoning from analogy had proved 
misleading. A specimen was found which, upon comparison 
with the second form mentioned above, rendered it almost 
certain that they were the two sexes of one species. It con- 
tained a male organ similar to that of the supposed new 
species, and upon further investigation specimens were found 
containing ova together with the other sexual structure. ‘This, 
therefore, it now appeared, was in reality the ovipositor. 
Upon further examination I found a minute structure of the 
same type present in the true A. strigata, of which the male 
remained still unknown. Hleven specimens of this form 
were all of the same sex, and as twelve of the form enigma, 
Arrow, which I have now, by Mr. F. Bates’s kindness, been 
able to examine, prove to be all males, the two occurring in 
the same collections, it can, 1 think, be safely assumed, not- 
withstanding all dissimilarities, that these also are the two 
sexes of a single species. 
The other species, so long confused with A. strigata, shows 
less sexual disparity and, this question of sexual forms once 
disposed of, is an unmistakably distinct insect. It is normally 
larger, broader, and darker in colour, with a triangular head, 
from which the eyes do not project laterally. This species 
may, I think, with practical certainty be identified as A. vitta- 
ticollis of Fairmaire. Unfortunately the type of this and 
allied Madagascan species described by that author cannot be 
traced, as M. René Oberthiir has kindly ascertained for me; 
but although M. Fairmaire’s specimen appears to have been 
smaller than any I have seen, his reference to the much- 
thickened lateral margin of the prothorax and the inner pair 
of black spots near the hind margin appear to undoubtedly 
indicate this insect. 
Herr Brenske has had the great kindness to send me his 
specimens, and so enabled me to determine the correct nomen- 
clature of these species. As I supposed, Adorodocia strigata, 
Waterh., is the insect called by him A. latissima, while 
A. maxima, Brenske, was described from a female specimen 
