60 
ORTHOPTERA. 
on cockroaches are egg-parasites ; the ichneumons of the genus Evania 
lay their eggs in the egg capsules of cockroaches and the household 
species are not exempt from attack. Field cockroaches are attacked by 
fossorial wasps of the genus Ampulex, which sting them, deposit them 
in holes or crevices and lay an egg on them. The unpleasant odour of 
the household cockroaches is probably protective and is due to the se¬ 
cretion of liquid from glands placed between the 5th and 6th abdominal 
segments. (Minchin, Q. J. M. S., XXIX.) 
It is known that cockroaches contain internal parasites belonging 
to the Gregarine division of the Protozoa, as well as parasitic bacteria, 
Nematodes ( Oxyuris ), Hair worms ( Gordius) and a Filaria. It is also 
probable that the large centipedes which enter houses in India are 
seeking blattids. Rats also feed on 
cockroaches. 
The family is a comparatively large 
one, with many described species, 
occurring in all parts of the globe. 
The majority of the Indian species 
are described by Brunner and Bolivar. 
Kirby’s recent catalogue of the fami¬ 
ly lists 123 Indian species, which 
probably include the majority of the 
larger forms. The family is being 
listed by R. Shelford in Genera In- 
sectorum; it is divided into eleven 
tribes by Brunner, but it is unneces¬ 
sary to consider these in this place. 
Phyllodromia (Blatta) germanica, Linn. 
Fig. 10— Phyllodromia humber- „ n 
ti an a. x 2§. is one of the common small species 
found in houses in India and now cosmopolitan, probably introduced 
to India from Europe. P. humbertiana , Sauss. (cognata) (fig. 10) is a 
small brown species, the prothorax marked with black and light brown. 
It is perhaps the most common field species, found among decaying 
vegetation and also on trees ; its eggs are laid on the leaves and bark of 
trees. On the soil is its wingless nymph, a small black insect with me¬ 
dian and lateral light stripes. Phyllodromia suppellectilium , Serv., is 
