ORDER ORTHOPTERA 247 



in a pair of long, unsegniented filaments (anal cerci) like those 

 of a cricket. Hemimerus talpoides, from tropical West Africa, 

 is parasitic on a rat {Cricetomys), and is further peculiar in 

 bringing forth its young alive. 



Family Blattida (Lat. blatta — a beetle). This family 

 includes the cockroaches, of which there are many species 

 besides the familiar kitchen pests. Cockroaches are dis- 

 tinguished by their flat body and strongly deflexed head, 

 and by their large coxae, which completely cover the weak 

 sterna of the thorax. In both sexes segmented anal cerci 

 are present, though in some cases they are small and con- 

 cealed ; and the males also have a pair of anal styles. The 

 adults may be either winged or wingless. The eggs are 

 laid in chitinous capsules shaped something like a bean ; but 

 viviparous Blattidse are known. The usual domestic species 

 are the dark-coloured Periplaneta orientalis, the lighter 

 coloured Periplaneta americana, and the small Phyllodromia 

 germanica. The habits of these are only too well known. 

 They seem to eat everything ; but they do more damage 

 in warm countries than they do in England, where they 

 seldom leave the moisture and warmth of cellars and culinaria. 

 Though no specific charge has been brought against the 

 domestic cockroach, it is quite reasonable to infer from the 

 habits of the insect that in its contact with food and utensils 

 it sometimes must be an agent of infection. On the other 

 hand, the cockroach is said to have almost a predilection for 

 bed-bugs as prey. Where cockroaches are a nuisance, their 

 haunts may be treated with creasote, or dilute formalin, which 

 are more lasting in their effects than insect-powder. The 

 intestine of the cockroach is the home of several interesting 

 Protozoa and worms. 



Family Mantidce (^ai'T£? = a soothsayer). The Mantids, 

 or Praying-insects, are recognised by the peculiar form 

 and attitude of the front pair of legs ; these are much 

 enlarged, and in repose are folded and uplifted as if in prayer ; 

 in action, however, they are formidable instruments for 

 striking and grasping prey, the tibia closing on the femur as 

 the blade of a pocket-knife shuts on its shaft, and the opposed 



