330 NATURAL ARRANGEMENT OF INSECTS. 



rior femora, a structure observable in other genera of 

 this family group, as we see in Oncomera, Nothus, and 

 (Edemera : these are, however, as is usually the case 

 with anomalous structural features, a characteristic of 

 the male insect only; an observation still further exem- 

 plified in the most extraordinary antennae of the male 

 Cerocomce, the description of which would scarcely convey 

 a distinct idea of the confusion of so heteroclite an organ. 

 The same sex of the same insect has an equally re- 

 markable developement of the maxillary palpi ; but some 

 of the most striking instances of curious palpigerous 

 structure, we shall find in the next family. In Nemo* 

 gnathusandGnathium, cognate genera, we find the max- 

 illae elongated into two slender filaments, half as long 

 as the body. This circle seems to present several con- 

 necting points with other groups ; thus, we have at once 

 an instance of it, by means of Notoxus, which, by the 

 way, is remarkable for its produced thorax suspended 

 over the head, through Scydmcenus and the Pselaphidce, 

 to the Predatores. We have also, from the vicinity of 

 this point, in the attenuated elytra of Sitaris, a genus- 

 parasitical upon Osmia, one of the mason bees, an in- 

 timate link of connection with the fourth family of this 

 circle, the Mordellida ; but it is evidently through Py- 

 rochroa that we approach our next family : 



(293.) The Lymexylonidce, the name of which ex- 

 presses at once their economy and habits, for in their 

 larva state they are excessively destructive to timber. 

 Indeed, one of them, the Lymexylon navale, was found 

 so injurious to the ship timber in store in the dock- 

 yards of Sweden, that Linnaeus was consulted upon the 

 best mode of checking the ravage ; and upon ascertain- 

 ing the true cause, he suggested a very effective one, 

 by the immersion of the timber under water during the 

 breeding period of the insect. The most striking 

 feature in this small group of insects, all of which are 

 pentamerous, (consisting, as yet, of only three genera ; 

 for we doubt if Cupes and Rhyssodes belong naturally 

 here,) is the remarkable maxillary palpi in their males: 



