518 THE ZOOLOGIST. 



an area, say eight square miles ; but I am not sufficiently acquainted with 

 them to know whether this is an unusually large number. 



Perhaps the few succeeding notes, such as they are, may be of use and 

 interest to you. I reached this locality in the end of July, when there 

 were apparently no Cicadas about. The little blackish species, Tibicen 

 nigricans, Stal, was the first to appear, which it did during the second 

 week in August, remaining till the end of September. Its call is quite 

 distinct from all the other species, and not nearly so loud. It consists 

 merely of a short chirp, hanging slightly on one note, and ending with a 

 quick rise, the sound being incessantly repeated. The next species, 

 Platypleura rutherfordi, Dist., began calling in the middle of Septem- 

 ber. I made no particular note of its cry, except that it was much 

 louder than that of the former, and continuous. It t was apparently 

 confined to the smoother trunks of the "mosasa" tree. It continued 

 calling until Oct. 15th, when I shifted camp four miles away. At this 

 spot it did not occur, owing, I presume, to the fact that the " mosasa " tree is 

 not found there, being replaced by a very nearly allied species, called by the 

 Kafirs " mfuti." However, when I went back on the 22nd I could not 

 find any of them. At my new camp, on Oct. 17th, I caught three species. 



The species, Pcecilopsaltria marshalli, Dist., occurs only on " mopani ' 

 trees, frequenting the smaller branches, to which its colouring is very well 

 adapted. Indeed, I have found it to be one of the most difficult to detect, 

 which doubtless accounts for the fact that it is the most easily approached, 

 and sits very close. Indeed, I have often struck the branch on which one 

 has been sitting, sharply with my net, without disturbing it. Its cry is the 

 most monotonous of any species I know, being one continuous unbroken 

 churr. I noticed a Cicada calling among " mopanis " in the end of Sep- 

 tember, which was probably this species. It disappeared in the middle of 

 this month. 



Pcecilopsaltria bombifrons, Karsch, is not confined to any one tree, but 

 frequents the small, smooth branches of many trees and shrubs. Its cry 

 has a considerable range, starting on a somewhat low note and gradually 

 rising to a high pitch, then falling again, and so on. I once came across 

 a very large concourse of this species, there being quite sixty on a small 

 bush, and making a terrible noise. At the first sweep I took two males 

 and five females, and of the twenty I caught only six were males. By the 

 way, I have noticed several facts which would lead me to suppose that 

 Cicadas were polygamous, and I should be much interested to know 

 whether your experience would bear this out.* 



* Polygamy is quite probable, though in the Transvaal I had reason to 

 believe that one species paired during the breeding season (' Naturalist in 

 the Transvaal,' p. 67).— En. 



