242 PERCY SLADEN TRUST EXPEDITION 



such as France and California. Certain apparently allied genera [Nesomicrops and 

 Macranillus) occur in the Hawaiian Islands (see Sharp, Fauna Hawaiiensis, vol. iii., part 

 iii. 1903, pp. 286 — 7, etc.). The preponderance of affinities of the Seychelles Carabid- 

 fauna is therefore seen to be with Madagascar and Africa. 



In the case of the Dytiscidse, the Seychelles possess, in the 2 species of Copelatus 

 {C. gardineri and C. pandanorum), a truly endemic element in their fauna. Both of 

 these are found in the high parts of the islands. C. gardineri, which is practically the 

 only water-beetle found in the streams in the mountains, may possibly be related to 

 certain Madagascar species ; but I have not been able to find any species closely related 

 to C. pandanorum, which is attached in a very special manner to certain endemic trees 

 (see p. 259*). With regard to the other two Dytiscidse found in the Seychelles, Bidessus 

 peringueyi is an Afro-Madagascan species, while Hydaticus leander is very widely 

 distributed (South Europe, Africa, Syria, Madagascar). 



If the Adephagan fauna of the Seychelles be compared with the Lamellicorn- fauna of 

 those islands [a^ite, p. 218), certain differences are apparent. In the Adephaga, the truly 

 endemic element is proportionately smaller: the relationships of the non-endemic species do 

 not point in so many directions, but are predominatingly Madagascan and African ; there 

 is no Eastern element in the Adephagan fauna such as that which is brought into the 

 Lamellicorn-fauua by the presence of Parastasia coquereli, nor are there any South-Asiatic 

 species corresponding to the two Cetoniines Oxycetonia versicolor and Protcetia aurichalcea. 



B. Aldabra Group. The subspecies trilunaris of Cicindela melancholica is, as 

 stated above, a Madagascan and East African form. Of the 6 species of Carabidae found 

 in Aldabra, Pheropsophus humeralis and Tetragonoderus hilunatus (which also occurs in 

 the Seychelles) are Madagascar species ; Tachys hihidus is known from Madagascar and 

 the Mascarene Islands ; Hypolithus pulchellus occurs in Madagascar and in Africa, 

 having been described from the far side of that continent (Senegal) ; Hypolithus 

 pavoninus is an East African species, while Dioryche interpunetata, which occurs also in 

 Coetivy Island, is widely distributed, being known from West Africa, Madagascar, the 

 Mascarene Islands, and the Coromandel coast of India. 



Of the 10 species of Dytiscidse, 4 {Laccwphilus iMsticus, Laccophilus addendus, 

 Hydrovatus humilis and Bidessus capitatus) are Madagascar species ; 2 [Hyphydrus 

 impressus and Copelatus pulchellus) are Afro-Madagascan, occurring in Madagascar, the 

 Mascarenes, and very widely separated parts of Africa ; one species {Canthydrus notula) 

 is Tropical African, not known from Madagascar ; while 2 [Ei'etes sticticus and Cyhister 

 tripunctatus) are very widely spread, the former having a world-wide distribution. 



The predominant Madagascan and African affinities of the Aldabra Adephagan fauna 

 are therefore evident. 



C. There remain 2 species, both Dytiscidse, which were found neither in the 

 Seychelles nor in the Aldabra Group. The former, Bidessus thernmlis from the Chagos 

 Islands, is a widely distributed species, represented by various forms in Southern Europe, 

 North and West Africa, Egypt, Arabia, Persia, and Bengal. The other species, Bidessus 

 farquharensis from Farquhar, is described as a new species. 



* Also cf. the bottom of p. 218. 



