78 APPLIED ENTOMOLOGY 



The adult is from one-half to three-fourths of an inch long, pale brown 

 with two darker brown stripes. It is very active and increases in 

 numbers very rapidly. 



The American Roach (Periplaneta americana L.). This is the largest 

 of the house roaches, being from one and one-fourth to one and one-half 

 inches long when adult. It is brown, darker than the German roach, 

 and has a more or less definite yellow band around the margin of the 

 pronotum (Fig. 47). It is a native of the warmer parts of this country 

 but has spread north and is now abundant everywhere except in the 

 most northerly states. 



The Australian Roach (Periplaneta australasice Fab.). Somewhat 

 smaller and apparently broader than the last, and with the yellow 

 band around the prothorax brighter, and a yellow streak on the costa 

 of the fore wing extending part way toward the tip (Fig. 48). It is 

 particularly common in the Southern States. 



The Oriental Roach (Blatta orientalis L.). This insect is the " black- 

 beetle" of Europe. It is almost black and the wings in the adult male 

 are considerably shorter than the body, while in the female they are 

 hardly more than stubs. It is a stout-bodied insect, quite generally 

 present in the eastern, southern and central United States as far west 

 as the great plains, and is the most common species in Europe (Fig. 49). 



Other kinds of roaches are occasionally found in the Northern States 

 brought there in bunches of bananas or with other southern fruits, but 

 they do not appear to be able to live long in the colder climates. 



Control. Various materials are more or less effective as roach killers, 

 but the best of these is commercial sodium fluorid. It may be mixed with 

 flour or some other inert substance, but nothing is gained by this except 

 a reduction of the cost of treatment and the killing may not be as rapid. 

 The powder is thoroughly dusted where the roaches occur, particularly 

 in their hiding places, using a dust gun or blower. The insects which 

 by crawling or in other ways get the dust on their antennae or legs, clean 

 these parts by drawing them between their mouth parts so that the 

 powder enters the mouth and probably acts through the alimentary 

 canal. 



Family Mantidae (The Mantids) 



The Mantids are usually quite large insects with bodies much longer 

 than wide, and a broad head which moves very freely upon the thorax. 

 The prothorax, with few exceptions, is very long, and bears legs adapted 

 for grasping the prey and which are well provided with spines, the in- 

 sects walking on the other four. In nearly all members of the group 

 the wings are well developed, the hinder pair larger and folding in 

 plaits when at rest with the other pair on the back of the abdomen. 

 They are often called Rear-horses, Devil-horses, Soothsayers, Praying 

 Mantids or Mule Killers. 



