10 
length; they are unsegmented and provided with fine, long hairs. 
Their function is uncertain, but is probably sensory. The genito-anal 
orifice is terminal and is controlled by a three-lobed valve, one lobe 
of which is dorsal and the other two sublateral. In the male the pos - 
terior margin of the eighth abdominal sternum is produced into a 
central tooth which is docked at the tip. (See PI. II, fig. D.) In 
the adult female there are only seven visible ventral segments in the 
abdomen (see PL II, fig. E), for the eighth, which is of lighter 
color than the rest and is not medianly prolonged into a tooth, is 
hidden by the seventh plate. This sexual difference can be clearly 
distinguished as early as the sixth instar, when, in the male the 
sternal tooth appears as a small median knob on the posterior margin 
of the sternum. 
DEFENSIVE AND STRIDULATING ORGANS. 
When disturbed the changa almost invariably ejects a fetid fluid 
from the anal orifice. Sometimes this fluid is expelled as a drop, 
which remains in place, but usually it is ejected to a considerable 
distance. The fluid itself is colorless or nearly so, but is usually 
discolored by the presence of soil particles. It is viscid, gives an 
alkaline reaction, and has a penetrating and unpleasant odor. Ac- 
cording to Baumgartner (5) it is probably a product of Du Four's 
organ. All instars secrete this liquid and its use, no doubt, provides 
a very effective defense against enemies approaching from the rear. 
The stridulating apparatus of the changa is simple. The under 
surface of the prominent transverse vein of the male tegmen bears a 
series of transverse chitinized ridges which gives the vein a filelike 
appearance. The characteristic chirp of the sex is made by " ruffling " 
the tegmina, so that the inner margin of one tegmen is drawn back 
and forth rapidly against the filelike vein of the other. The note 
produced is a short shrill chirp seldom lasting more than two or three 
seconds. Baumgartner (5) notes the presence of " feebly developed" 
stridulating organs on the female tegmina and concludes from his 
observations that the female also chirps. The writer has never heard 
the female make any note whatever. 
LIFE HISTORY. 
REMARKS ON BREEDING WORK. 
The breeding work with the changa, summarized in this paper, 
was done in the insectary at Mayaguez, and all statements as to 
seasonal activity, duration of instars, and the like, are made for that 
locality only. It is likely that there is not much variation in the 
insect's life history at different points on the coastal plain, with the 
possible exception of the drier southern coast. The rainfall probably 
