6o 



THE STUDY OF INSECTS 



Recently two exotic species have been introduced into the Northern 

 States, probably by the importation of oothecae on nursery stock, and 

 have become established here. These are the Mantis religiosa of Europe, 

 which was first observed in this country near Rochester, N. Y., in 1899, 

 and Paratcnodcra sinensis of China and Japan, which was first observed 

 here at Philadelphia about 1895. 



Family Blattid^; 

 The Cockroaches 



The cockroaches are well-known insects with oval depressed bodies, 

 long slender antennae and legs fitted for running. The head is bent 

 downward and the mouth-parts project backwards between the first pair 

 of legs. 



After every one is in bed at night and all is quiet in the kitchen where 

 there are water-pipes, often a throng of these small creatures come forth 

 from hiding-places and, like brownies, take possession of everything. 

 They race around everywhere, trying to find something to eat, almost 

 anything that comes in reach of their greedy jaws. They eat book-bind- 

 ings and bedbugs, if they find them, with equal alacrity. 



Fig. 103. — The Croton-bug; a, first instar; b, second instar; c, third instar; 

 d, fourth instar: e, adult; /, adult female with egg-case; 4', egg-case, enlarged; 

 h, adult with wings spread. All natural size except g. (From Howard and 

 Marlatt.) 



Not only are these insects very destructive to our possessions, but 

 owing to their fetid odor merely the sight of them awakens disgust. 



The eggs of cockroaches are enclosed in purse-like capsules (Fig. 103, g). 

 These capsules, or oothecae, vary in form in different genera, but are more 

 or less bean-shaped. Within, the ootheca is divided into two parallel 

 spaces, in each of which there is a row of separate chambers, each cham- 

 ber enclosing an egg. The female often carries an ootheca protruding 

 from the end of the abdomen for several days. It has been found that 

 a single female may produce several oothecae. Probably the most effec- 

 tive means of ridding premises of cockroaches is by dusting the places 

 they frequent with commercial sodium fluoride. 



In the Northern States our native species are usually found in the 

 fields or forests under sticks, stones, or other rubbish. But certain im- 

 ported species become pests in dwellings. In the warmer parts of the 

 country, however, native and foreign species alike swarm in buildings of 

 all kinds, and are very common out of doors. 



