6 
FRESHWATER AND LAND CRAYFISHES OF AUSTRALIA 
terrestrial in habit, bnt a few species are equally at home in 
water and in burrows in dry or moist soil. Both aquatic and 
terrestrial forms crawl on land, especially in wet weather, and 
this habit probably accounts for their presence in artificial 
dams and ponds distant from natural lakes, swamps or water- 
courses. 
In each genus there are both aquatic and terrestrial species. 
For example, in Gherax there are aquatic species ( bicarinatus , 
tenuimanus ) ; semi-aquatic, i.e, living in ponds and water- 
holes which often dry up during the summer months ( destruc- 
tor , albidus , quinq uecarina tus ) ; and terrestrial (punctatus) . 
Engaeus, although usually a terrestrial genus, has species 
which live in creeks as well as on land in such localities as 
Skipton, Ferntree Gully and Marysville, Victoria. 
Both aquatic and terrestrial species are burrowing animals ; 
the former burrow in submerged, the latter in moist or dry 
soil. Aquatic species do much damage to retaining walls of 
channels and dams, and to banks of rivers and streams. Ter- 
restrial species are sometimes serious pests in orchards where 
they burrow under roots of trees, and in some pastoral dis- 
tricts where large community burrows are numerous and 
collapse under the weight of cattle and horses. At Whitegate, 
a few miles from Benalla (Victoria), some areas riddled by 
yabbies are practically useless and are known as “crab-hole 
country.” 
Burrows of the various species of Engaeus are similar to 
those of the North American genus Cambarus, which have 
been described and figured by Ortmann, Abbott, Harris and 
Tarr, and the habits of both genera agree closely. Some 
species have burrows for only one occupant ; others have com- 
munity burrows for numerous occupants. The two genera 
also agree in including species which live in creeks as well 
as in burrows in soil. Ortmann ’s method of collecting speci- 
mens (1906, p. 345), by digging them out with a bayonet, is 
not much use when dealing with the Victorian species of 
Engaeus ; a pick and shovel are the best collecting implements 
as many of the burrows descend six or seven feet. 
Little has been published on the life history and habits of 
the Parastacidae. From observations made in Victoria and 
Tasmania during the past two years the breeding season is in 
spring, following the period of moulting, when numerous egg- 
bearing females were taken. During December and January 
females with newly-hatched young attached to the swimmerets 
were collected. While carrying eggs or young the females 
are particularly vicious, brandish their large chelae threaten- 
