678 EXTERNAL ANATOMY OF INSECTS. 



you will find very prevalent in the Coleoptera Order, 

 as in the Predaceous and numerous other beetles : in 

 the Orthoptcra and Hemiptera Orders, however, I have 

 not discovered an instance of it ; but in all the rest it 

 more or less occurs : next to this number — Mice with 

 obsolete or no spurs seem most prevalent, particularly in 

 the Hemiptera; not a single instance of an insect fur- 

 nished with them occurring to me in the Heteropterous 

 section ; and it is doubtful whether there are any in the 

 Homopterous. — Having stated the most universal struc- 

 ture in this respect, I will next consider the Orders se- 

 riatim. Amongst the Coleoptera though the numbers 

 2:2:2 are most frequent in occurrence, yet there are 

 numerous exceptions. Thus, in the Lamellicorns, 1:1:1 

 represents the calcaria of one tribe of the Scar aba?i dee M c Ju. 

 formed of the genus Scarabaus M C L. ; 1:2:1 represents 

 those of another tribe of that family, including the sub- 

 genera Ateuchus, Copris, Phanceus, &c; 1:2:2 again 

 forms the character in this respect of ApJwdius and the 

 great majority of the Lamellicorns; while 2:2:2 is con- 

 fined in this section to JEsalus F. and Melolontha chryso- 

 meloides Schranck (Psephus M C L. MS.). In the other- 

 tribes of Coleoptera other numbers occur. Thus, 0:1:1 

 characterizes Hylcecetus; 0:1:2 Mordetta ; 0:2:2 Ma- 

 cropus; -]-:2:2 Harpalus, and all those Carabi L., ex- 

 cept Zabrus, that have a notch in their anterior tibial; 

 £:2:2 Zabrus. In the Orthoptera Order it is not easy 

 to distinguish the real spurs from the implanted spines 

 that frequently arm the legs : these in Blatta are ex- 

 tremely numerous, even at the apex of the tibiae ; but I 

 cannot distinguish any that can be regarded as true ana- 

 logues of the former : the most natural number of spurs 



