THE DEVELOPMENT OF MALPIGHIAN TUBULES IN DYSDERCUS 

 KOENIGI F. (HEMIPTERA, PYRRHOCORIDAEf^ 



Развитие мальпигиевых сосудов у клопа Dysdercus коепгдг F. 

 (Hemiptera, Pyrrhocoridae.) 



и. S. SRIVASTAVA and J. В A HADUR 

 (Department of Zoology, University of Allahabad, India) 



SUMMARY 



Dysdercus koenigi has two pairs of Malpighian tubules, each pair arising from a com- 

 mon vesicle and forming a loop by joining each other at the distal end. The vesicles are 

 connected to each other dorsally by a short canal and the Malpighian tubules are dif- 

 ferentiated into distinct proximal and distal regions. 



In December-January at Allahabad, its embryonic period lasts for about a fortnight, 

 and when the embryo is nine days old, four small buds arise apparently from the anterior 

 end of the proctodeum. These grow rapidly by active mitosis of cells, become tubular 

 and the tips of the two tubes fuse, but their lumina remain separate. At this time, a mem- 

 brane (met-enteric membrane, H ens on, 1946) stretches over the anterior end of the 

 proctodeum, but actually extends from the posterior end of the mid gut and the zone 

 of origin of the tubules lies between the membrane and the proctodeum. An interstitial 

 ring now differentiates in the proctodeum, so that the zone of origin of the tubules lies 

 just anterior to it. Meanwhile, the basal region of each tubule swells and the swellings 

 of the two tubules of each side fuse, thus forming a common vesicle from which the two 

 tubules forming a pair arise. A dorsal ovitgrowth from each vesicle ultimately meets its 

 fellow of the opposite side, so that now the vesicles communicate with each other. The 

 tubules continue to elongate, at the same time becoming narrower; thus ultimately only 

 three large cells can be seen in a cross section. The period of growth of the tubules can 

 be divided into three consecutive stages: period of active mitosis only; period of cell pro- 

 duction by mitosis and cell rearrangement; and period of cell rearrangement and cell 

 enlargement. Finally, the tips of the tubules of each pair fuse competely and their lumina 

 beconie continuous. 



In the newly hatched First Nymph, there is no differentiation of the tubules into 

 proximal and distal regions and no differentiation of striated or brush border in the cells, 

 but these characters are gradually acquired in the later part of this stage, showing that 

 the embryonic development continues for some time in the first nymphal stage. Once 

 this condition has been acquired, cyclical changes, including increase in the diameter 

 of the tubule, size of the nuclei and number of cells in the proximal region of the tubules, 

 occur in each nymphal stage, but before ecdysis, the diameter of the tubules decreases 

 slightly. Thus the adult condition is reached in five distinct steps, corresponding to the 

 five nymphal stages. Meanwhile, the vesicles become enveloped by a thin muscular layer 

 towards the end of the first nymphal stage. 



Henson (1932) has argued that the interstitial ring represents the posterior half 

 of the blastoporal lip and hence the region anterior to it, including the zone from which 

 the Malpighian tubules arise, is endodermal. He (1946) also agrees that the met-enteric 



*) The detailed report will be published later. 

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