110 MICHIGAN ACADEMY OP SCIENCE. 



13. The Distribution of the Unionidae in Michigan. Bryant Walker. Published 

 by the author. 



14. A Leaf-miner in Water Lilies. Rufus H. Pettff, B. 8. Printed in this report. 



15. Some Modifications of the Zeiss Microphotographie Apparatus. Jacob Roig- 

 hard, Ph. B. Published in present report under the title "Apparatus foi' Photo- 

 graphing Vertebrate Embryos." 



16. The Habits of Eucleniensia bassettella, a True Parasite Belonging to the Lep- 

 idoptera. Rufus H. Pet tit, B. S. Printed iu this report. 



17. On the Effects of Temperature on the Development of Animals. F. R. 

 Lillie, Ph. D. Published (in conjunction with P. P. Knowlton) in Zoological Bul- 

 letin (Ginn & Co.,^ Vol. I, pp. 179-193. 



18. The Hind brain and Cranial Nerves of Acipenser. J. B. Johnston. Pub- 

 lished in Anatomischer Anzeiger. XIV Band, Nr. 22 and 23, 1898, pp. 580-601. Re- 

 print of summary of results in this report. 



19. Origin and Structure of the Cell Plate. H. G. Timberlake. 



20. A Natural History Survey of Michigan. Presidential address. Volney M. 

 Spalding, Ph. D. Published by the Academy, 1S98. (Copies may be obtained from 

 the Secretary.) 



21. Nature Study in the Common Schools. W. J. Beal, Ph. D. Substance printed 

 in a series of eight bulletins published by the Agricultural College under the head- 

 ing "Elementary Science." 



A WORD FOR SYSTEMATIC BOTANY. 



BY W. J. BEAL,. 

 (A brief abstract.) 



The author believes that most students acquire a first love for botany 

 by rambling over the fields, through forests and swamps. This brings 

 them in contact with a great variety of plants in various stages of growth 

 and arouses their curiosity to learn their names and places in the plant 

 kingdom, and incidentally they desire to learn their habits and peculiar- 

 ities. Any young person is sure to have his interest awakened, if he is 

 accompanied by a congenial friend who is a botanist. 



A LEAF-MIXER, CHEIRONOMUS SP. } IX WATER LILIES. 



BY R. H. PETTIT, AGRICULTURAL, COLLEGE. 



So far as is known to the writer, the members of the genus Cheiron- 

 omus are tube-builders in their larval stages. They are small flies closely 

 resembling mosquitoes and the larvae inhabit the water where they act 

 the part of scavengers. These larvae are usually blood-red in color 

 and very small and slender, rarely exceeding % of an inch in length. 

 They build tubes out of particles of vegetable matter and carry these 

 tubes about with them much as do caddice-flies. However, if at any 

 time the larva wishes to leave his dwelling he does so and if, after wander- 

 ing about for a time, be is unable to find his home, he soon builds another 

 just as good. This seems to be the general habit of the members of the 

 genus. An exception was found last summer in which the larvae made 

 tubes but built them of fresh green material and made them fast in a 

 furrow or minute ditch cut in the upper surface of a water-lily leaf. 



