104 THE ENTOMOLOGIST, 
not associate species with entirely unarmed tibie with those that 
have any of them spinulose. I have yet to find a species in which 
this feature varies, either as to the absolute presence or absence 
of spines, or as to the number of pairs of tibie furnished with 
them. The character separates no closely allied species within 
my knowledge. Besides this armature of spinules, the fore tibia 
is very frequently furnished with one or a series of stouter, more 
claw-like processes, and frequently it is abbreviated or chitinized. 
This armature or its variations can be used in many cases, but is 
subject to considerable variation, and is of the same relative im- 
portance as antennal structure. The wings afford good generic 
characters by their shape and proportions, and usually groupings 
made on marked wing forms will be found to afford other 
distinctive features. Venation is important of course; but this 
is of use mainly in divisions higher than generic, and is very con- 
stant throughout the family. Mr. Butler has recently insisted 
strongly, and I am inclined to believe justly, upon the division 
proposed by Guénee into Trifide and Quadrifide, based on the 
position of vein 5 of the secondaries. 
In some of the Bombyciform Noctuids there is a tendency to 
lose the accessory cell of primaries, and this is sometimes a good 
character. It must be carefully used, however; for I have seen 
a specimen where the cell was normal on one wing and absent on 
the other; while in other specimens of one species all forms of 
development, from no cell at all to one that was complete, have 
been found. In the Deltoids the neuration of the primaries often 
becomes aberrant, and furnishes good generic characters. Differ- 
ences of thoracic vestiture, whether composed of hair alone or 
scales alone, also furnish good bases for generic division in some 
cases and in some groups. In others the differences are specific 
merely. The tuftings of the thoracic vestiture are of considerable 
value, and peculiar developments, as in Cucullia for instance, will 
run constant through a long series of species. Abdominal 
structures are few, and the tuftings only have been made use 
of in generic separation. They are unsatisfactory, and of very 
unequal value. 
I have made no reference to the class of modifications that 
are called secondary sexual. These may occur on almost any 
part of the body, and are usually given generic value. The legs 
and antenne are most usually the bearers of these peculiarities. 
The primary sexual structures have thus far furnished specific 
characters only in the Noctuide, and I do not care to venture 
an opinion upon the question of a greater range for them at 
present. 
The characters are not numerous; but they serve for 
numerous combinations, and they leave room for a great 
deal of individial opinion. Mr. Butler has, in his arrangement 
of the Noctuide in the British Museum, placed values on 
