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OF THE ANTENNAE OF INSECTS. 387 



terminal joint, which is more elongated than the rest : they consist of the smaller and 

 larger sort, as in SUpha, but arranged in a manner very peculiar, and confined to the 

 lower half of the terminal joint. The smaller forms are disposed in groups of from six to 

 sixteen in each. The groups are diamond-shaped, with a row of hau-s between them : at 

 the angle are occasionally found the larger organs, as in SUpha, as also a few scattered on 

 the upper half of the joint. Their covering-in membrane, however, is not so conical. 

 The diameter of each of the smaU organs is sx^ inch. (Sec C. fig. 1.) 



In Goerius olens the organs are distributed thickly over the surface, rather more fre- 

 quently than the hairs, and show theu- sacculated nature very well (D. a a). 



In Carabus there are eleven joints in the antenna; only the last five possess the organs. 

 They are not so numerous as those I have described before, and are principally placed on 

 one side of the antenna, as sho^vn in E. 



In all the species examined of this genus, I have found the closing- in membrane raised 

 considerably above the surface-level, more so than in SUpha, and having six or eight ridges 

 running from apex to base, as is shown in E. figs. 2, 3. The greatest diameter of the sac 

 is tbVo inch, vvhUe that of the closing-in membrane at the surface is yoou inch. The 

 Section, fig. 1, shows the form of the sacs and closing-in membrane. 



In six species of Elater which I have examined, I find the same conditions, namely : 

 chiefly on the serrse of the joints, generally in front of the base of the hairs, are smaU 

 sacs about -^^j^q inch in diameter, as is shown in E. figs. 1, 2 « & b. The closing-in mem- 

 brane is slightly raised above the surface ; and on the apex are from three to six, generally 

 four, smaU. papillae or tubercles, as is shown in E. fig. 2 S, & fig. 3. 



In Strangelia elongata these sacs are very numerous, disposed over eight of the twelve 

 joints, and becoming larger and more frequent towards the apex. They are generally situ- 

 ated in front, or near the roots of the hairs ; and their closing-in membrane is much smaller 

 than the diameter of the sacs beneath. These sacs vary much in size, being from xtVo to 

 6 0^0 inch in diameter. The larger sort seem convoluted, or two- or three-chambered. 



The ant.enna3 of the Musk Beetle {Aromia moschata) are very similar ; and the same 

 description will apply, except that the sacs are larger than the above. 



In Cetonia aurata the three lamellae are furnished with sacs, which are placed close 

 together, and are found on both sides of the middle one only, and on that side of the first 

 and third which is in contact with the middle one. 



In the antenna of Dtjnastes Hercules the sacs are very numerous, and the covering-in 

 membrane weU marked, their diameter being about -^roo inch. They are found on the 

 same parts of the lamellae as in Cetonia aurata. In consequence of the sacs not extending 

 through the whole thickness of the antenna- wall, a tube passes from the inner aspect of 

 each to connect it with the interior of the lamella : towards the margin of the lamella the 

 form is modified, the sac being placed halfway within the thickness of the integument ; 

 and there is not only a tube connecting it with the interior, but also a smaller one extend- 

 ing to the outer surface (H. figs. 1, 2). Numerous depressions, in some cases forming 

 cavities, are to be found in the anteima ; and in all the LamcUicorns I have hitherto 

 examined, the sacs are situated on all portions of these depressions, which are thus common 

 to them. 



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