100 PARTIAL ORISMOLOGY. 



tinguish the OPEN wings (patentee) by the angle which they form with 

 the axis of the body? being at least of 45 ( Tabanus, Musca, &c.). The 

 ERECT-OPEN wings (erectee patentes) do not lie in the same plane with 

 the body, but cut it at an angle of less than 45 (some Lepidoptera, for 

 example, Hesperia). 



CONNIVENT (conniventes), are such wings which, in repose, perfectly 

 unite with each other at their corresponding margins (Papilio] ; 

 DIVARICATED (divaricate), are such which only partially cover each 

 other (Agrion). 



DEFLEXED (defle.vai), are such which, with their internal margin, 

 meet at an acute angle, and so cover the body (many Noctuce) from 

 them must be distinguished the REVERSED wings (reverses') by this, 

 that the anterior margin of the posterior wing projects bevond the 

 same part of the anterior wing (Gastrophaga alnifolia) ; this is also 

 often the case in the open wings. 



B. THE LEGS. 

 81. 



The other chief organs of motion, the LEGS (pecles), are distinguished 

 from the wings in a multitude of ways, in form and number, as well as 

 in their function. 



In number, they exceed that of the wings by one-half; for although 

 we never observe more than four wings, we constantly find, in perfect 

 insects, six legs. These six legs are placed in pairs upon the lower 

 part of each of the three segments of the thorax, and consist of many 

 joints, to the observation of which we now pass. 



We have already become acquainted with the ACETABULA (ace- 

 tabula') upon the segments or plates of the breast, for the reception 

 of the legs. 



I. These cavities receive pieces formed exactly to their dimensions, 

 frequently conical, or more longitudinal and rounded, called the HIPS 

 (coxae, PL XVI. f. 1, ). Surrounded and enclosed by a corneous 

 substance, it has, only at each of its opposed ends, an opening for the 

 passage of the muscles which unite it to the surrounding parts. This 

 typical form of structure is somewhat modified by the closer or looser 

 union of the coxae with the thorax ; so that it appears sometimes as a 

 cone truncated at its apex, and then attached to the thorax by the 

 whole of its basal surface (Diptera, Lepidoptera, Hymenoptera, &c.); 

 and sometimes moves itself freely in a proportionate cavity of the 



