191 
The student of Pyralidce will find that he must study the male 
secondary sexual characters very carefully in distinguishing species 
and that they occur with great frequency in a very marked form. One 
of the commonest male characters, is a greater apparent development in 
the antenn 3 e and this is shown in most moths, the female having often 
simple antennae while the male has them ciliate, pectinate, fasciculate 
or modified in some way. Were more known of the actual habits of 
moths, we might be able to say whether these modifications gave the 
male a greater chance of finding the female, for instance, by giving the 
antenna a more delicate or special sense. At present nothing is known 
and there is no real information as to how insects find each other. This 
development of the antennae is a feature also of Culicidce, with a more 
astonishing difference in the relative development of the palps, those 
of the males being very much larger. There is also a surprising devel¬ 
opment of the antennae in the male Lampyridce in species in which the 
luminescence is little developed. 
We cannot leave this subject without briefly touching the problem 
that every student finds of determining the sex of an insect. It is ex¬ 
tremely irritating to find, for instance, characters given for the males 
only, while one has not enough of a species to have both sexes and one 
does not know, without dissection, what is the sex of the specimen one 
has. To deal adequately with this subject would require very many 
pages and a separate treatise. In some families sex-distinction is easy, 
as in Locustidce , Gryllidce , Acridiidce , many Parasitic Hymenoptera , and 
those groups which have a distinct ovipositor. In others there is no 
such obvious distinction, and in some families dissection is actually ne¬ 
cessary. This is the case, for instance, in the bulk of the Rhynchota , 
Heteroptera ; Distant is discreetly silent in the Fauna of India on this 
point except where such obvious differences occur as in Physorhynchus. 
In some species, the possession of claspers points to the males ( Lepto - 
corisa), the larger bodies and distended abdomen of the female some¬ 
times marks the female (Dysdercus, etc.). Coupling unfortunately 
affords no evidence as these forms couple in opposition. (Coupling is 
by opposition in Lepidoptera and Hemiptera , by superposition in Coleop- 
tera , Orthoptera, Diptera and Hymenoptera). Coleoptera is another 
order in which there is no one characteristic of the male. There are 
abundant small characters in different families, but they must be 
learnt for each. In Orthoptera , the matter is simpler ; in Forficulidce 
the male has nine, the female seven abdominal segments ; the genital 
styles mark the male Blattids; the male Mantids have two more visible 
ventral segments (eight, really nine), than the female (apparently six, 
really seven). The female Phasmid has the egglaying gutter or process ; 
while the Acridiid female has two pairs of digging processes ; Locustid 
and Gryllid females have usually an ovipositor. In Rhopalocera , the 
male sex marks are usually distinguishable in the form of glandular 
hair patches ; in moths, Hampson has pointed out that the frenulum 
is simple in the male, compound in the female. In Diptera the 
