DRAGONFLY COLLECTING IN INDIA. 
897 
trigone and one other nervure spring from a small, oblique nervurc called the 
“ arc ” and the space basal to this is called the “ arcular space,” whilst the 
space immediately below this latter is the “ cubital space.” 
About the middle of the costa will be seen a kind of rigid jomt which is called 
t he “ node ” and the small vertical nervures internal to this are called the 
“ antenodal nervures,” whilst those external to it are the “ postnodal nervures.” 
The antenodal nervures are split up into two sets by a nervure which runs trans- 
versely through them and it is to be noted that in some species the two sets cor- 
respond whilst in others they do not, that is, they are independent of one 
another, 
Li the Zygoptera the place of the trigone is taken by an oblique or squarish 
space called the “ quadrilateral ” and the adjacent structures are modified as 
will be seen in the figures. 
2. The Head. 
The head consists largely of two large compound eyes, the “ occiput,” lying 
between and behind them, and the 
up of 
-lower 
Fig. 4. — A. Head of an Anisoptera full 
face. B. Ditto {OompMne.) C. Head 
of a Zygoptera. 
1. Labrum (or upper lip), 2. Labium (or 
lower lip), 3. Eye, 4. Frons, 5. Vesicle, 
6. Ocelli (or accessory eyes), 7. Occiput, 
8. Nasus or epistome, 9. Aniennoe. 
“ face.” The latter is made 
the lips (labium and labrum 
and upper lips), the “ nasus ” or 
“epistome” which corresponds to 
the position of the nose and lastly 
the upper part of the face or fore- 
head which is kno\vn as the “ frons ” 
(Fig. 4). 
3. The Thorax. 
This is made up of a small part 
immediately behind the head, the 
“ prothorax,” which bears the first 
pair of legs and a large bulky part 
carrying the second and third pairs 
of legs and the two pairs of wings, 
the “ synthorax.” 
The posterior part of the upper 
surface of the prothorax is of impor- 
tance in some species for purposes of 
classification, and is knovm as the 
“ posterior lobe.” 
The front and upper surface of 
the thorax is its “ dorsal ” surface, 
whilst the part to one side of this, 
correspondmg to our shoulders, is 
called the “ humeral region.” The 
sides posterior to this region will be 
seen to hare two false joints, the 
“ sutures.” 
The legs consist of the same parts 
as in the butterfly, viz., the “ coxa,” 
“ trochanter,” “ femur,” “ tibia ” 
and “ tarsus ” or “ claws.” The 
femur, tibia and the shape of the 
claws are the only parts used in 
classification. 
4. The Abdomen. 
This is the long, narrow x^art im- 
mediately following the thorax and 
is made up of ten segments. The 
abdomen may be moderately short 
and stout, or long, or excessively 
