82 



THE ORDER OF COLEOPTERA. 



The following are the two principal genera : 



A. Club of autcnuiu small witli the plates of equal thickness ; size medium or above : color dark me- 

 tallic {jieen or purple, sometimes black Geotuyi-ks, 7. 



A A. Club of antennm large and compact with the plates of unequal thickness ; size below medium ; 

 <'olor brown BousocEitus, 3. 



The G. splendidus, Fab., is our most common species, 

 usually about seven-tenths of an inch long, but varying 

 considerably in size, and varying also in color from dark 

 metallic green to purple. G. excrementi, Say, is a little 

 more than five-tenths of an inch in length, and of a 

 bronze-black color. G. opaciis, Hald., is of a dee^) black 

 color, and varies in length from a little below to a little 

 above half an inch ; it is much rarer than the other two 

 species. The elytra are not furrowed like the others, but 

 only marked with lines of minute punctures. The Bolbo- 

 beetie; '2,"mandi. cerws farctus, Pauzcr, is half an inch long, brownish-yel- 



blew : '■i, antenna, .,,,.-, • n,ivi j.i i.i 



showing the large low, With the hind margin of the thorax, the sutural 



il'oso°ciub'',"'a^idliiie, and the broad tips of the elytra black. B. Lazarm^ 



joint is eLased in Panzer, Is four-tcuths of an inch long, and wholly of a 



after westmwiT mahogany-brown color. B. Jilicornis, Say, three-tenths 



of an inch long, of the same color as the last, and distinguished by a 



slender horn on the top of the head of the males, whilst the others have 



only tubercles. The last species has been separated from the others 



under the generic name of Odonfceus. It is also distinguished by ha\ing 



the eyes completely divided by the lateral margins of the head. 



Family XXIX. TROGID^. 



These insects are readily distinguished by their coarsely pitted thorax 



and ridged elytra. The other characters given in the foregoing table 



[ Fig. 37. ] are also very distinctive. They vary 



in size from more than a half to less 



than a quarter of an inch in length, 



t n u B^m""] u ^^^ ^^^ ^^ ^ uniform slateblacl:, or 



i//#^^^*«k^ brownish-black color. Their habits 



*« K ^'^apr K are but little known, but they are iisu- 



«' "^ ally found in sandy situatiojis, and 



tkox PUSTULATU8, LeC.:-a, larva: 6, pupa; c, sometimes u])on the carcasscs of <lead 



beetle ; rf, e, /, leg, cervical plate, and maxilla, ^ 



with palpi of larva enlarged— after Eiley. auimals. Mr. E-ilcy breeds TvOX 'pUH- 



tulatus (Fig. 37.) from dead chickens. They are comparatively rare in- 

 sects. They are sonunvhat niinuMous in species, but are all included in 

 the genus Trox of Fabricius. 



