154 [December. 



but the species does not appear to have been described, so that I give 

 below a description of it. Its nearest ally is no doubt the Assamese 

 Seliocopris domina, Bates, and the two species appear to be of about 

 the same size : the largely developed male of Seliocopris domina is, 

 however, described as possessing four horns on the head, to be less 

 black in colour, and to have the intervals on the elytra sub-convex. 



In connection with the description of this remarkable insect, I 

 may be permitted to mention what has long been a favourite theory of 

 mine, viz., that as we proceed from the lower to the higher forms in 

 some of the groups of Lamellicorns, we find a better construction of 

 the skeleton, causing the parts of the body to be much more accurately 

 adapted to one another, and that, as the result of this perfection, there 

 is a much greater immunity from the attacks of minute parasites. 

 Oeotrupes is a form in which the construction is very imperfect, and 

 the result is that the species are dreadfully subject to the attacks of 

 Acari, which not only overrun the individuals outwardly, but obtain 

 access to the soft parts of the body, and no doubt destroy a vast 

 number of individuals ; to so great an extent is this the case, that I 

 believe the species of Geotrupes only continue to exist because the 

 more perfectly constructed Coprophagous Lamellicorns are yet only 

 adapted for existence in warm climates, and Geohnipes, therefore, finds 

 in temperate latitudes an abundant and comparatively uncontested 

 pabulum, which enables it at present to hold its place, notwithstanding 

 other disadvantages. 



The species of Seliocopris offer a beautiful example of the accurate 

 coadaptation of the external parts, by which is obtained a nearly com- 

 plete exclusion of parasites from those parts of the body which are 

 most accessible in less perfected Coprophagous Lamellicorns ; the 

 elytra in Seliocopris are so beautifully adapted to the mesothorax, 

 metathorax, and ventral and dorsal segments, that not even a minute 

 parasite can obtain access to any of the soft dorsal surfaces of these 

 parts, although, on making an examination of a Seliocojjris, we should 

 be justified in concluding that it would be very diflicult for an Acarus 

 to find sustenance on its juices by getting at the soft parts of the body, 

 yet an examination shows that there are still some parts not sufiSci- 

 ently protected, and on these parts it appears the Acari still mainta' i 

 their attacks. As most accessible, we find the very large mouth. The 

 buccal cnYitj in Seliocopris is greatly developed, and formed of unusually 

 soft pieces, and offers abundant facilities for the entrance of a small 

 invader by its large and unprotected orifice. Thus I was not surprised 

 on cleaning the individual of Seliocopris MouJiotus from Cochin China 



