THE HABITATS OF INSECTS. 



is also the case with the Trichocera hiemalis, Meig., for it is not rarely 

 that we find it upon clear sunny winter days, dancing its choral round 

 in the air over the snow. Others, again, present themselves only with 

 and upon the snow, as Boreus hiemalis, Lat., a genus allied to Panorpa, 

 but wingless, which is not rare in woods upon warm winter days ; as 

 also the Podurce, which swarm like black dust sometimes upon the sur- 

 face of the snow; and, lastly, the equally apterous Chionea araneoides, 

 which belongs to the Diptera, with many jointed antennae, and which 

 Dalman * has described, and which, according to him, is found in 

 Sweden upon the snow at a temperature of 2 3 (of the scale divided 

 into a hundred). 



If we now cast a glance upon the time of appearance of tropical 

 insects, the information we have yet received upon this subject is so 

 imperfect, that scarcely anything satisfactory can be deduced from it. 

 According to the letter of Westermann to Wiedemannf, at Kiel, which 

 is so interesting from the intelligence it gives us of the habits of many 

 tropical insects, insects are found in Java, Bengal, and at the Cape, only 

 during the rainy season, during which the whole tropical vegetation is 

 in its highest luxuriance, and they then swarm upon flowers and leaves, 

 seeking nutriment. Where they conceal themselves during the hot 

 season is not yet known with certainty, yet they doubtlessly seek places 

 of retreat similar to those sought out by our own during winter. Thus 

 the hot temperature of a tropical summer has the same effect upon 

 insects as the cold of winter with us, and what lures them from their 

 hiding places with us, drives them there into their concealed places of 

 resort. Yet it is the same law which is in force, and by which insects 

 are especially bound to the luxuriant increase of the vegetable kingdom, 

 for it is only during the warm rainy season that tropical plants are in 

 blossom, and they are then visited by insects of all descriptions. 



* Analecta Entomologica, p. 33. -f- Germar's Magazin, vol. iv. p. 411,&c. 



