LARVA OF TANYPUS MACULATUS. 83 



complete separation is effected, and the young animal thenceforth 

 leads an independent life. Not unfrequently, however, before its 

 detachment a new set of segments is developed in front of it, 

 which in like manner are provided with a head, and separated 

 from the main body by a partial constriction ; and the same 

 process may be repeated a second^ and even a third, time, so that 

 we may have in this animal the extraordinary phenomenon of 

 four worms, which are afterwards to exist as separate individuals, 

 united end to end, receiving nourishment by one mouth and 

 possessing one anal orifice/' Strange to say, this passage is 

 quoted by Dr. Williams as "an illustration of the extraordinary 

 degree to which the groundless fancies of the older observers 

 have taken captive the imagination of the moderns." It is a pity 

 that a work replete with interesting and valuable information 

 should be marred by such a positiveness of assertion, which, as 

 Dr. Johnson truly says, " is unhke that with which a prudent 

 man dealeth with knowledge." I would remark, in conclusion, 

 that two or three segments of this worm are provided with 

 pulsating vessels, viz. — those immediately following the head — a 

 feature which is denied them according to the synoptical table of 

 Claparede, "^ but distinctly recognized by O. Schmidt, t I also 

 observe that the blood-corpuscles are lenticular, presenting their 

 edges as they roll over ; and the small setae are simply hooked, as 

 shown in Figs. 5 and 6. 



®u tbc Xarva of ^an^pue flDaculatue. 



By a. Hammond, F.L.S. 



Plate 8. 



THERE appears to be some confusion about this insect. 

 Walker:!:, curiously enough, describes the larvae of two species 

 of flies — viz., of Tanypiis maculatiis and Tanypus monilis. 

 His description of the latter is exactly that of the subject of this 

 paper, that of the former being very different, as inter alia he 

 speaks of its having ten legs. Having thus led his readers to 



* Memoires de la Soc. de Phys. de Geneve, Tom. 16, p. 221. 



t Ann. des Sci. Nat., 3rd Ser., 7 and 8, 1847, p. 183, 



\ Insecta Britannica, vol. 3, pp. 197 — 8. 



