THE CANADIAN ENTOMOLOGIST. 257 



hardly .12 mm. in length. The resemblance to the structure of the eighth 

 abdominal spiracles of Donacia is, however, most striking, and, with the 

 exception of the inner structure of the appendages, is complete. This 

 difference, I think, can readily be accounted for and the evolution of a 

 type of spiracle like that of Donacia larvae be shown from a simpler form 

 as found in these Hispid pupae. 



The life-history of D. crassipes has already been intimated. I do not 

 know that the life-history of D. piscatrix has been carefully studied, but 

 from facts obtainable I would judge it to be as follows : The eggs, 

 which are of a brown colour, flattened oval in shape, about .75 by .25 

 mm., are laid in a double row, the line between the two rows being 

 formed by the ends of the eggs, 20 to 30 of which are laid in a bunch. 

 These are deposited early in summer on the roots of NympJieas, upon 

 which the larvae feed. The cocoons are found on the roots or sometimes 

 on the stems of water plants, and the beetles emerge either in the early 

 fall or remain in the cocoons till the next spring. 



The larvje of Hcet/wnia are much the same, the specimens I have 

 seen being shorter, and plumper, with the abdominal appendages 

 extending ventrad almost perpendicularly and covering the caudal 

 segments. The best characteristic between the two genera is the loss of 

 the ocelli in Ilcemonia, which I judge is the more specialized genus. I 

 have been unable to observe the prothoracic spiracle mentioned by 

 Lacordaire. 



Certainly, altogether, the larvae of this tribe are most distinct from 

 those of all other Chrysomelida;, possibly even more so than are the adult 

 beetles. 



EXPLANATION OF FIGURES. 



Figures are from camera-litcida drawings by the author, except Figs. 17-20. 



Fig. I. — -Antenna, Donacia piscatrix. 

 11 Donacia crassipes. 



^ - II Haemo7iia zoster ce. 



4. — .1 Crioceris merdigera. 



5. — 11 Chrysoniela varians. 



7 

 8 



9 



10 



n Haenionia nigricornis. 



-Labrum, Donacia crassipes. 

 11 Donacia piscatrix. 



II Haemonia Jiigricornis. 



II Haemonia zosterce. 



