INSECT LIFE IN INDIA AND HOW TO STUDY IT. 183 



This family would appear to be well represented in Assam, most of the 

 species in the Indian Museum collections coming from that locality. It 

 would be most interesting if any one serving in that part of the continent 

 would take up and work out this most curious, as it is interesting, 

 family. He would be able to obtain help from the Indian Museum 

 collections which, thanks to the intimate knowledge of the group pos- 

 sessed by the late Mr. Wood Mason, a former Superintendent of the 

 Museum, are systematically arranged and contain a large number of 

 species. 



Series Saltatoria. 



Hind legs elongate, formed for leaping ; their femora usually 



thickened. 



Fam. V. Acridiidae— Locusts. 



The hind legs differ from the others in being more elongate and 

 in having their femora broader near the base. Antennas short and 

 thick, with less than 30 joints. There is no exserted ovipositor in the 

 female. Tarsi are short with three distinct joints. The auditory organ 

 is placed on the upper part of the side of the first abdominal segment. 

 The large head is joined to the thorax in one piece, the front being 

 deflexed downwards at a sharp angle. Besides the two compound eyes 

 there are three ocelli (small simple eyes, see Fig. 2) present. The 

 upper wings are roof-shaped. 



This family is remarkable owing to the presence of air sacs in connec- 

 tion with the trachea in the interior of the Insect and it is doubtless 

 the possession of these which enables them to undertake the great, 

 flights they perform when migrating. 



The chirping sound of locusts is produced by rubbing together the 

 outer face of the upper wing, one of the veins in which is prominent 

 and possesses a sharp edge, and the inner face of the hind femur, 

 which bears a series of small bead-like prominences placed on the 

 upper of the two lower ridges which run along the side that is nearest 

 to the body. 



The Acridiidae include the grasshoppers of the fields and the 

 important migratory locusts of this country and other parts of the 

 world. The family contains more species and individuals than any 

 other Orthopterous family, and is a most important one, as all its 

 members feed upon growing plants. It includes what are perhaps 

 two of the most dangerous Insect pests in the world— the great North- 



