139 
ypts, their lair having two openings usually. While at rest in 
these, their head is near and toward one of the openings; the long, 
highly flexible antenne being stretched behind towards the other, 
so as to receive timely warning of the approach of an enemy or 
prey from that direction. When disturbed they prove very 
nimble and swift runners, but do not as a rule take to-wing 
in daylight or in wet weather, but do so at night, or even in 
cloudy afternoons before sunset. If handled incautiously they 
are able to inflict severe bites, drawing blood readily, their 
mandibles being very strong, sometimes of enormous size, and the 
largest in general among insects. Being carnivorous, they are 
highly beneficial in assisting to keep down other species that 
would be highly injurious to agriculture if increasing without 
check. 
I. GRYLLACRIDA. 
The GRYLLACRID#& are distinguished from all other Locustids 
(1) by the delicate, mantis-like structure of their wings, which 
are richly provided with veins and veinlets, but without 
tympanal organs; (2) the long, articulately-inserted, movable 
spines on the under side of the fore and middle tibie ; and (3) 
the lobe-like lateral expansion of the tarsal joints. The last 
abdominal segment of the male is also very abnormal, the eighth 
being usually enlarged, still more so the ninth, becoming cucul- 
late and enclosing the anal organs. Brunner has figured eight 
different types, without, I think, exhausting them. These, 
however, are scarcely generally useful for more than specific dis- 
tinction when both sexes are known, and assist in no wise the 
mating of individuals, because no corresponding structure or 
proportionate character exists in females. 
Presence or absence of wings forms a good character to separate 
the family into three groups, as the organs of flight are either 
perfect, more or less rudimentary or wholly absent. When rudi- 
mentary, it is easy, as pointed out by Brunner long ago, to 
distinguish adults from nymphs by observing whether the 
anterior or costal margin is directed upwards or downwards, the 
latter infallibly denoting the adult, the former the nymph-stage. 
The size, shape, and venation of the wing-lobes form good specific 
or even generic characters. 
The anterior (perfect) organs of flight, known as elytra or 
tegmina, are so richly and variably supplied with veins and vein- 
lets, that their venation is useless for the object of diagnosis, 
while the form of the apex can only be employed in closely-related 
species. 
The posterior or real wings, however, afford good characters for 
distinction by the various colouring of veins and membrane. 
