INSECT LIFE IN INDIA AND HOW TO STUDY IT. 



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Fam. II. Blattidae— Cockroaches. 



These are one of the oldest forms of Insects known, for it is certain 

 that in the carboniferous epoch they existed in considerable numbers 

 and variety, and the remains found do not differ very essentially in 

 appearance from present-day forms. The group contains about 800 

 species, divided into ten genera. 



The head is bent downwards, so that the mouth is on the under 

 part which is directed backwards. (See Fig. 6.) Antennae are very long 

 and flexible, bristle-like, and consisting of 75' — 90 joints ; they are 

 longer in the male than in the female. Their function is supposed to 

 be that of smelling. The body is very flat, ending in small flat 

 processes, the 'cerci' which are usually distinctly jointed. Long 

 strong running legs, with large free coxae and big femurs, are present. 

 Fig. 8 shows a dorsal view of an Indian cockroach Blatta sp. 



These Insects are common in houses, vessels employed in river and 



ocean traffic, &c. Their 

 larvae much resembling 

 the adults, but without 

 wings, are often to be 

 found in rotten stumps 

 of trees in the forests 

 and elsewhere amongst 

 refuse. As a family their 

 food is of a very mixed 

 nature. Periplaneta ame- 

 ricana (Fig. 6) is a cock- 

 roach of worldwide dis- 

 tribution and very com- 

 mon in houses in India. 

 It is perhaps the com- 

 monest Insect in Calcutta houses throughout the year. The so-called 

 " black-beetle," so common in London houses and elsewhere in England, 

 is a cockroach by name Periplaneta orientalis. 



Treatment. — Prepare a mixture of equal parts of finely powdered 

 chocolate and borax and dust it into the crevices where the insects 

 hide. The mixture must be well made so that with each part of choco- 

 late, of which the cockroaches are very fond, they will get a particle of 

 borax which is poisonous to them. The mixture is cheap and non- 

 poisonous to man. 



Fig. 8.— Blatta sp. (Johore) 



