1923.] Anatomy and Bionomics of Red Cotton Bug. 35 
men are small, in the thorax just opposite the metathoracic 
spiracle it gives off a branch wider than the main dorsal 
longitudinal trunk. This branch divides to aerate the stout 
muscles lying below the scutellum of the mesonotum. 
Of the two branches from the first thoracic spiracle the 
posterior joins the longitudinal trunk, whilst the anterior 
extends obliquely towards the median line of the head, giving 
small branches along its course and finally entering the base of 
the antennae. 
In Dysdercus cingulatus the ventral branches, unlike the 
condition in several other bugs (7, 2], 5), do not unite to form 
a ventral tracheal trunk. 
The ventral branch (Fig. 17a) of the first thoracic spiracle, 
at its base, gives off two branches—one large and the other 
small—to the first leg, a small branch to the second leg, an 
a stout branch which passes towards the median line and unites 
with asimilar branch from the opposite spiracle. Subsequently, 
the main branch divides into several minor branches which, 
along with the oesophagus, pass through the circum-oesopha- 
geal commissure to supply the soft parts of the head capsule, 
two of them passing through the rostrum to its apex. The 
ventral branch of the second thoracic spiracle gives one branch 
anteriorly to the second leg, and two branches (one large and 
the other small) to the third leg. It then runs across to unite 
with its fellow of the opposite side. ; 
The tracheae are supported internally by chitinous rings, 
although the diverticulum connecting the tracheae with spir- 
acles are devoid of such rings. : 
Stink Glands (Fig. 18).—These form a pair of small sac-like 
organs lying on the floor of the metasternum. They are red in 
colour and communicate with each other by a transverse tube 
which is bent backwards. Each sac communicates with the 
exterior by a slit-like opening in the anterior ventral part of 
the metathoracic pleuron. : 
Circulatory System.—This system of the cotton-bug is 
shown in Fig. 19. 
REPRODUCTION AND Lire-HisToryY. 
Some 40 hours after copulation the female becomes inac 
tive, the abdomen getting greatly distended with eggs. The 
eggs are laid in crevices of the soil usually in two lots, the 
first containing some 90 to 105 eggs and the second (following 
5-8 hours after the first) 50-70 eggs. A single egg is about 
1-25 mm. long (the long axis of the egg agreeing with the future 
long axis of the larva), pale yellow in colour, soft when newly 
laid, subsequently becoming somewhat hard (Fig. 20a). 
the required conditions of moisture and temperature are 
maintained, the egg, which is pale yellow at the time of laying, 
