160 Mr. Robert M'Lachlan on the 



lower part of each side of the last segment proceed the 

 enormous wp^pendices inferiores, which are long and broad, 

 extending nearly to a level with the apex of the superior 

 process, spoon-shaped, concave within and convex with- 

 out, and ending more or less obtusely. 



The above observations, and the accompanying figures, 

 have all been made by the aid of a |-inch power, with the 

 compound microscope, and the camera lucida. The 

 various parts lying nearly on one plane, and simple in 

 structure, were the more easy to examine in this way; 

 but much allowance must even here be made for the fact, 

 that dry-insects only were examined, and for the difficulty 

 of obtaining precise similarity of position and focal equality 

 in microscopic manipulation as applied to these objects. 

 In some individuals the various parts are closed one 

 upon the other, rendering their discrimination impossible ; 

 in others, the intromitteut organ is concealed under the 

 superior process. 



So far as I am aware, the only published figures or de- 

 scriptions of this apparatus, are those by Edwin Brown, 

 in Moseley's ' Natural History of Tutbury,' and by Kole- 

 nati (copied by Brown) in Wieu. Ent. Monatsch, vol. ii. 

 A comparison of their figures with those here given, 

 proves that they were drawn roughly without sufficient 

 magnifying power, the details of structure not being- 

 represented. 



I now proceed to apply the results obtained from my 

 investigations to the question of specific differences in 

 the genus. Taking the appendices inferiores first, I find 

 remarkable similarity in all the materials examined : but 

 in Staudinger's $ oi. A. latipennis, and in some indivi- 

 duals (of A. niveus) from Riugwood, these parts are 

 decidedly more acuminate, and more produced and acute 

 at the apex, and this is even not sufficiently indicated in 

 my figure, for, in consequence of the apex being some- 

 what incurved, it is much fore-shortened under a liigh 

 power. The boat-shaped lobe does not show any im- 

 portant variati(m. The process extending from this lobe 

 differs to some extent in the contour of its lower edge, 

 viewed laterally; and in one example from Ri^gwood, 

 there was even an evident subapical tooth -like projection. 

 In Staudinger^s examples of A. niveus, and in my own 

 examples from near Burton-on-Trent, the extreme apex 

 is curved downwards, and more acute. The intromittent 



