96 



W. A. LAMBORN. 



mud on the bottom. Occasionally a pupa may be seen rising slowly to the surface 

 with material from the bottom dangling from the caudal fins. It has been able so to 

 attach itself by means of a pair of booklets, one springing from the free margin of each 

 fin, and actually an extension of the thick chitinous bar, which forms a backbone- 

 supporting the fin. 



If one studies vagus pupae in a test-tube, one finds that for the purpose of maintain- 

 ing themselves below the surface, one of three common methods may be adopted, 

 according to the nature of the supporting material available. First, by preference 

 a pupa will get beneath the .supporting object ; secondly, if the object is of convenient 

 size it may clasp it with its anteflexed abdomen ; or thirdly, it may attach itself by 

 the caudal hooks, then rising above the support. Occasionally a pupa of vagus 

 has been seen upside down, attached to a rough support by means simply of one 

 respiratory trumpet, showing how slight must be the difference in specific gravitj- 

 between itself and the water in which it is found. Though the hooks (fig. 3) are present 



Fig. 3. Terminal segments of pupae of: (a) Anopheles 



subpictus, Grassi ; (ft) A. stibpictus var. vagus, Don.; [c) 



A. asiaticus, Theo. ; [d) A. hyrcanus. Pall. ; (e) A. tessellatus, 



Theo. ; (/) A. karwari, James. 



in the pupae of suhpictiis {rossi), maciilatus, kanoari, aconitus and fuliginosus, they are 

 represented in sinensis, barhirostris, umbrosus, kochi, tessellatus, asiaticus, and, curiously 

 enough, in aitkeni also, by a mere filament, and in these latter species, the pupa attaches 

 itself to an object by one of the two ways described first, or, in the absence of any 

 support, remains below by swimming efforts, renewed directly it tends to rise. 



The form of the hook varies a little in each species. In all it consists of a stout 

 bristle, which after a short straight course becomes recurved in the direction of the 

 dorsal aspect of the pupa, terminating in a rounded hook. The bristle itself is of brittle 

 material, for often one or both may be broken off short in pupae which have been 

 roughly dealt with. 



