Page:A note on grappling tail-hooks in anopheline larvae - M.O.T. Iyengar - 1922.pdf/8

Rh but they have no capacity to withstand a flush. In one instance, a good flush was able to drive all larvæ of culicifacies a mile down the stream.

Specimens of larvæ of A. maculipennis, Meigen, bifurcatus, Linn, and plumbeus, Haliday, received through the courtesy of Prof. G. H. F. Nuttall, were also examined. The hooks were quite typical in the two former, but in A. plumbeus, the hooks were very few and minute.

I have (through the courtesy of the Director, Zoological Survey of India) seen type specimens of larvæ of Anopheles annandalei, Prashad, a tree-hole breeding species from the Himalayas. I have observed that the hooks are present quite characteristically in this species also.

Postscript.—Just prior to sending this note for publication, I have seen a paper by W. A. Lamborn on the 'Nature and function of caudal tufts in malayan anopheline larvæ,' in the latest issue of the Bulletin of Entomological Research (Vol. XII, pt. 1, July 1921).

I wish to note briefly on some points raised by Mr. Lamborn. He believes that in previous literature, no structural differentiation of the two sets of (dorsal) brushes had been noted' (p. 92). It should be pointed out that Nuttall and Shipley in their articles on the 'Structure and Biology of Anopheles maculipennis' (Journal of Hygiene, Vol. 1, pt. 1, 1901) have clearly described and figured these tufts. Their figures and descriptions are perfect, though they missed these hooks.

Mr. Lamborn says 'The presence of any hooks at all in the case of ''A. subpictus var. vagus'' and others which breed by choice in the still waters of muddy pools is doubtless to be explained by recent modifications of breeding habits; for until the advent of the white man to this country and the subsequent great economic development, there must have been comparatively few such breeding places available.' It is here assumed that these hooks are quite useless in stagnant waters; this statement is fully controverted by my note. It is too much to assume that there were few stagnant waters before the advent of the white man; and there is no evidence to show that there has been any 'recent modification of breeding habits.'

Mr. Lamborn notes that tree-hole breeding species have imperfectly developed hooks. I have not seen A. asiatica. A. plumbeus larvæ from England show this reduction, but the hooks are present though few and feeble. But as stated above the larvæ of A. annandalei Prashad, also a tree-hole breeder, show no such reduction, the hooks being quite well developed. There is no evidence about the other tree-hole breeding species.