THE ENTOMOLOGIST. 37 



ihe pursuit of honey hums continually and contentedly on a', 

 but if it is excited oi' angry it produces a very different note. 

 Thus, then, the sounds of insects do not merely serve to 

 bring the sexes together ; they are not merely " love-songs," 

 but also serve, lilie any true languoge, to express the feelings. 

 Dr. Landois describes the muscles by means of which the 

 form of the organ is altered, and the tone thus, no doubt 

 voluntarily, affected. We can indeed only in a few cases, 

 distinguish the differences thus produced ; but as even we, 

 far advanced as we are in organization, habits and senti- 

 ments, from a fly or a bee, can yet feel the difference between 

 a contented hum and an angry buzz, it is highly improbable 

 that their power of expressing their feelings should stop 

 here. One can scarcely doubt but that they have thus the 

 power of conveying other sentiments and ideas to one 

 another. 



Opening the Spiracles. — In conjunction with M. Thelen, 

 Dr. H. Landois has also communicated to the Zeits. f. Wiss. 

 Zool. another memoir, on the means by which the spiracles, 

 or rather the trachea) immediately behind the spiracles, are 

 opened or closed. The mechanism consists of four principal 

 parts — the bow, the lever, the band, and the muscle. The 

 contraction of the latter, acting on the lever, causes the band 

 and bow to meet, and thus close the passage. When the 

 muscle relaxes, the natural elasticity of the parts causes 

 them to separate again, and thus leave the tracheal tube 

 open. They describe the details of the apparatus in a con- 

 siderable number of species. 



Ocelli of LnrvcB. — Dr. H. Landois has also published a 

 memoir on the ocelli of caterpillars. After describing them 

 in detail, he comes to the conclusion that they do not essen- 

 tially differ from compound eyes, and that if many of them 

 were grouped together they could hardly be distinguished 

 from compound eyes. In each so-called ocellus the cornea 

 is divided into three lenses, corresponding to three nerves, 

 each with a separate terminal enlargement forming the so- 

 called crystalline bodies. Each ocellus therefore might be 

 regarded as in reality composed of thi'ee. On the other hand, 

 the three arches of the cornea are so closely connected 

 together that they give the impression of forming a single 

 cornea. The three lenses also are very closely pressed, and 



