THE CANADIAN ENTOMOLOGIST. 219 



during this summer were found upon the leaves. If these latter were 

 floating, the larvae were exposed on the upper surface, in other cases they 

 were beneath or concealed in folds. A different habit of swimming to 

 that of Arzama obliquata, which progresses by horizontal undulations 

 was noted. E. caduca swims strongly, but by an entirely different motion. 

 The posterior third of the body is bent downwards like the tail of a 

 crayfish and then quickly pushed backwards, thus driving the insect 

 ahead by jerks. 



Discussed by Messrs. Weed, Webster and others. 



Prof. Cook reported having bred Agrotis C-nigrum through all its 

 stages upon black currant, the eggs having been laid in a cluster upon 

 leaves of that plant on istofjune — the perfect insect appearing on the 

 ist of August. 



Prof. H. Osborn read a note on the " Period of Development in 

 Mal/opkaga.''' The habits of the species oi Mallophaga render accurate 

 observations upon the time required in development of the eggs a matter 

 of considerable difficulty. While in some of the species upon very 

 common birds it is possible to get an abundance of material, in other 

 cases the opportunities for obtaining such material are very rare. But in 

 the most common species the difficulty of determining the exact time of 

 deposition of eggs, and then of keeping individuals in such conditions as 

 to insure a normal development, makes positive observations difficult. 

 This being the case, any observations which may add to our knowledge 

 of the subject seem of interest, and the present note is offered as one 

 such contribution. 



The species chosen in the present case is the Nitzschia pulicare, 

 which is almost invariably to be found in abundance on the common 

 chimney swift ( Chatura pelasgia). This bird is an abundant resident 

 of the building in which my laboratory is located, and being readily 

 obtained on account of its tendency to fly in at the windows, I suggested 

 to Mr. P. H. Rolfs, a graduate student in biology, that he attempt the 

 rearing of larvae from eggs with a view to determine length of develop- 

 mental period in connection with studies of its embryology. 



For this first purpose he secured on two separate occasions a number 

 of the eggs, and kept them, part in a tight paste-board box, which 

 was kept warm by the heat of his body, the others were enclosed in 



