INSECT LIFE IN INDIA AND HOW TO STUDY IT. 



191 



fore wings are very short and oval, and the hind wings are rolled 

 up upon themselves like 

 a rolled-up umbrella and 

 extend back in two points. 

 (See Fig. 21.) This in- 

 sect is dangerous, as it 

 burrows under ground 

 in grass lands, "gardens 

 and nurseries, destroying 



the roots of plants in its FlG> 2L _ The mo i e . C ricket Gryllotalpa vulgaris, 

 operations. (Bengal) f. 



The second injurious species which has proved itself a serious pest in 

 India is a cricket (Fig. 22) named Brachytrupes achcetinus,* which has 

 a very wide distribution. The life-history of this insect has been partially 

 worked out by the writer and an Assistant in Eastern Bengal (Chittagong 

 Hill Tracts). Larvee about half grown were found in April voraciously 

 feeding upon young rubber (Ficus elastica) seedlings in nursery beds, 

 into which the young plants had been transplanted from the pots in which 

 they had been raised from seed. It was not until some 40 per cent, of 

 the seedlings had been killed off that the aggressor was marked down in 

 the burrows in which it lives. These are constructed in soft sandy 

 situations, the tunnel starting at an angle to the surface level and 

 running in a zigzag manner down into 

 the soil for some 2 feet and having a dia- 

 meter of \ to f inch. At the end it is 

 enlarged into a small chamber. A hole 

 may be occupied by one, two, or as many 



as three young ones. The insect feeds 



.1 i. Fl °- 22 -— Common field-cricket. 



chiefly at night, spending the day in its Brachytrnpetachcetinu*. (Chitting 



burrow, into which it drags some of Hill Tracts.) \ nat. size, 



its food plant for consumption during the day. Soft soil is chosen to 

 dig the holes in — and therefore the nursery beds are preferred, but any 

 soft spots in the neighbourhood will be found to contain numbers of the 

 insects. The young larvee feed till the beginning of the rains — about 

 the middle of June. They then cease until October, and they would 

 appear to rest during the heaviest of the rains, though there is no pupal 

 stage proper in this Order. In October the damage in the nursery re- 

 commences, and the holes will be found to contain two fully developed 



* See Departmental Notes on Insects that affect Forestry, No. 1, p. 6. 



