686 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXVI. 



The following is a list of species found. 



Ovthefrum sabina very common. 



Diplacodes triviality ,, ,, 



Diplacodes nebulosa scarce* 



Trithemis pallidinervis common. 



Trithemis aurora aurora very scarce. 



Trithemis aurora aurora juo „ „ 



Crocothemis senilia common 



Zy. comma petiolatum „ 



Brachythemis contaminata very common. 



Brachydipla.i sobri)ia scarce. 



Totamarcha obscitra common. 



Tan tala ft a vescen s , , 



Indothemis caesia scarce. 



Bradinopyya yeminata common. 



Rhyothemis larieayata „ 



Rhyothemis phyllin one female. 



Acisoma imnorjjoides panorpoides common. 



Tholymis tillarya ,, 



Tramea Limbata only one specimen 



seen, not taken. 



By far the commonest species were Orthelrum sabina and Diplacodes trivialis. 

 It would be difficult to tell which was the more common. The former 

 swarmed in the hedges and shrubs, while the latter seemed to prefer the 

 grassy spots of the " maidans " and the sides of roads. Hardly a square 

 yard of the grassy plains around the Mount were free of D. trivialis. 

 None were found over water. The females were more numerous than the 

 males, which latter when mature are exceedingly active and difficult to 

 catch. Colour changes due to maturation are very marked in this species, 

 the full grown male being a handsome insect of a dark slaty blue frosted 

 over, while the juveniles are of a pale yellow with scarcely any markings. 

 All gradations between the pade yellow and the fully matured slate-blue 

 insect were taken, the colour contrast is very striking. 



Associated with D. trivialis, and like it, a very low flying insect, a few 

 specimens of D. nebulosa were taken. This insect was very scarce and the 

 adult male is even more active than trivialis. Females were somewhat 

 more common than males. 



In common with several other species of Odonata, O. sabina is at times 

 markedly gregarious. Its distribution on these occasions is very local. 

 Small areas can be found swarming with it to the exclusion of other species. 

 In one plot of ground, during the month of March, they could be taken 3 or 

 4 at a time with each sweep of the net. This little plot of ground was not 

 more than twenty yards square. I noticed the same thing in connection 

 with R. varieayata. In all my excursions in this neighbourhood I saw only 

 one specimen of this tribe (Rhyothemis), flying high in the gardens of the 

 Agri-Horticultural Society, Mount Road, Madras. The Chetpat llailway 

 station, however, literally swarmed with these beautiful insects. They even 

 flew into the railway carriages. I took several pairs on the platform, but 

 on searching the fields and tanks around the station I failed to see a 

 single specimen. The station employees could give no information as to 

 whether they appeared there every year ; in fact they had not noticed 

 their existence until questioned, in spite of the extraordinary numbers 

 present. 



Another species, with similar local habits, is B. geminata. Large numbers 

 can be taken off the north wall of the Church of England cemetery, St» 



