COMPARATIVE CHROMOSOME DATA ON TWENTY THREE SPECIES OF FAMILY COENAGRIONIDAE (ZYGOPTERA : ODONATA)

Karyological investigations have been carried out on 23 species of seven genera belonging to family Coenagrionidae. These have been collected from states of North-west and North-East India during pre-monsoon and post-monsoon Seasons. Among these, 21 are male species and 4 are female species. In males, 16 species reveal 2n=27 as diploid chromosome number and 2n=25 in remaining five species. In females, all the species possess 2n=28 as diploid chromosome number. All the species have XO-XX type sex determining mechanism. Autosomal fragmentation has been observed in Agriocnemis obscura (9), Ceriagrion coromandelianum (d), Coenagrion dyeri (9), Pseudoagrion decorum (d) and Pseudoagrion rubriceps (d&9). Chromosome number varies from 27-60 in gonial metaphase plates. Sex element could not be differentiated in the fragmented stages. Behaviour and morphology of chromosomes during meiosis have been studied and compared within family and within genera.