EXTERNAL ANATOMY OF INSECTS. 677 
2: 2:2; this you will find very prevalent in the Coleo- 
ptera Order, as in the Predaceous and numerous other 
beetles: in the Orthoptera and Hemiptera Orders, how- 
_ ever, I have not discovered an instance of it; but in all 
the rest it more or less occurs: next to this number—- 
tibie with obsolete or no spurs seem most prevalent, 
particularly in the Hemiptera ; not a single instance of 
an insect furnished 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 structure in this respect, I will next consider 
the Orders seriatim. Amongst the Coleoptera though 
the numbers 2: 2: 2 are most frequent in occurrence, yet 
there are numerous exceptions. Thus, in the Lamelli- 
corns, 1:1: 1 represents the calcaria of the genus Scara- 
beus ; 1: 2:1 represents those of another tribe of that 
family, including the subgenera Ateuchus, Copris, Pha- 
naus, &c.; 1:2:2 again forms the character in this re- 
spect of Aphodius and the great majority of the Lamelli- 
corns; while 2: 2: 2 is confined in this section to salus 
and Ochodeus chrysomelinus. In the other tribes of 
Coleoptera other numbers occur. Thus, 0: 1:1 charac- 
terizes Hylecetus ; 0: 1:2 Mordella ; 0:2:2 Acrocinus ; 
1:2: 2 Harpalus, and all those Carabi L., except 2abrus, 
that have a notch in their anterior tibie ; 4: 2: 2 Zabrus. 
In the Orthoptera Order it is not easy to distinguish the 
real spzwrs from the implanted spznes that frequently arm 
the legs: these in Blatta are extremely numerous, even 
at the apex of the ¢idi@ ; but I cannot distinguish any 
that can be regarded as true analogues of the former : 
the most natural number of spurs in this Order is re- 
presented by 0: 0: 4; this you will see in all the Locusts’ 
