HABITS AND LIFE HISTOKIES OF TABANID^. 



37 



consequently one has an excellent opportunity to watch the procedure. 

 The accompanying illustration (fig. 11) was made from a photograph 

 of a living specimen which was found in the act of egg- laying and 

 carried, with the leaf, to the laboratory where the picture was taken. 

 During the whole time she continued ovipositing without showing any 

 signs that she was aware of what was going on or that she had any 

 concern for the welfare of her eggs. 



The method of placing the eggs is similar to that recorded for C. 

 callidus in my paper on "The Tabanid^ of Ohio,"" pages 1- and 5. 

 The female alights on the leaf with her head downward and begins the 

 process l)v pushing the tip of her abdomen for- 

 ward toward the under part of the thorax and 

 placing the protruding end of an o^gg against 

 the leaf. The end sticks fast in consequence of 

 the glue-like substance which accompanies it, 

 and she then moves the tip of her abdomen back 

 to its normal position, thus freeing the Qgg. 

 V>y similar movements one or two eggs are 

 placed to one side of the first, and two or three 

 to the other side of it. The unfinished end 

 soon becomes V-shaped; she moves slowly for- 

 ward and lifts the tip of her abdomen to one 

 arm of the V and places eggs along down until 

 the apex is reached; then changes to the other 

 arm of the V and places eggs along down to the 

 apex on this side. It was noted in specimens 

 of this species observed that sometimes a female 

 would place as many as three rows of eggs on 

 one side, one after the other, before changing 

 to the opposite side. It is only necessary to 

 stud}^ a mass of these eggs in order to see the 

 precision, in reference to one another, with 

 which the different specimens are arranged. 



The eggs (fig. 12) are placed on various aquatic 

 plants, oftentimes standing in rather deep water 

 and at times as much as 20 rods from shore. I 

 have always found them on scattering plants 

 around the edges of grassy areas and not back 

 among the dense growth; consequently they are 

 easily seen, not only on account of conspicuous location, but also 

 because of their shining black color, which contrasts strongly with the 

 green leaves to which the}' are attached. 



It has occurred to me that, on account of the uniform methods of 

 placing the eggs followed by various species and the strong contrast 

 of these eggs with their surroundings, there are times when hand 



Fig. 11. — Chrijso-ps mivrens 

 ovipo.siting. From a liv- 

 ing specimen (original). 



«Ohio State Academy of Science, Special Papers, No. 5, May 1, 1903. 



