On the Geographical Distribution of Insects. 339 



duces them considerably, and continues to do so more and 

 more till the end of November, when, as has been stated, the 

 rainy season resmnes its sway. 



At Rio Janeiro, situate exactly under the tropic of Capri- 

 corn, a different order prevails. Insects appear in September 

 with the first rains ; but, as the rainy season, though very se- 

 vere, is far from equalling that of Cayenne * in intensity, they 

 do not disappear on its attaining its maximum of violence in 

 January and February ; on the contrary, they go on increasing 

 along with the rains, and these two months are the most pro- 

 lific in the year. In April they diminish along with the rains, 

 and during the dry season, from May to the end of August, 

 scarcely any are to be found but Carabidae and Melasomas, 

 which have taken refuge under stones, bark, &c. 



At Buenos Ayres, 35° south latitude, the seasons of the ap- 

 pearance of insects are regulated nearly in the same manner 

 as in southern Europe, but in an inverse sense, on account 

 of the difference of the hemisphere. Insects appear in Sep- 

 tember and October in spring ; the powerful heats of mid- 

 summer (January and February) cause them to disappear, as 

 with us ; they again multiply in autumn (March and April) ; 

 and, finally, from May to the middle of September, only a small 

 jiumber are met with. 



Chili, situated under the same parallels as Buenos Ayres, 

 differs from it, in the view we are now taking, only in this, 

 that, rain being almost unknown from the middle of spring to 

 the middle of autumn, it is only at the commencement of the 

 former and the end of the latter that insects are common, 

 while at Buenos Ayres they are found throughout the whole 

 duration of these two seasons. 



Our acquaintance with other warm countries of the globe, 

 in regard to the subject of which we now treat, is limited to 

 what we have learned from M. Westermann respecting the 

 Cape of Good Hope, Bengal, and Java.-f- There, as in Ame- 

 rica, the condition of insects is in perfect accordance with the 

 dry and rainy seasons ; and as these two seasons act upon 



• The annual quantity of rain which falls in Cayenne, is about 130 

 inches, while it does not exceed 80 at Rio Janeiro. 

 + Germar's Magazin, torn. iv. p. 411. 



