TABANID^ OF OHIO. 5 



of her abdomen to one arm of the V and depositing eggs along 

 down until the apex is reached, then changing the tip of her ab- 

 domen to the outer part of the other arm of the V and placing 

 egg^ along down to the apex on this side. 



This process is kept up, the female changing regularly to 

 the outer part of the opposite arm of the V each time the apex 

 is reached. Between nine o'clock and noon seems to be the favor- 

 ite time of day for oviposition with the various species of both 

 ChrysQps and Tabanus, and I have seldom been able to observe 

 females ovipositing at other hours of the day. 



The eggs when first laid are clear white but gradually get 

 darker until they become permanently dark brown or black. 

 Most of the eggs of Chrysops are deep black, and are placed in" 

 a single layer, but there are exceptions to this, for the egg of 

 C. celer are never darker than brown, and are placed in at least 

 three layers one upon the other. 



The color of eggs in Tabanus is variable between brown and 

 black, and so far as 1 have observed, are always placed in convex 

 masses composed of layers one upon the other. In sections of 

 eggs just laid no great amount of development is observable, 

 and we therefore conclude that eggs are laid soon after they are 

 fertilized. Temperature has its influence on the incubation period, 

 and for this reason the length of time required for the hatching 

 of Tabanid's eggs can not be said to be exactly so many hours. 

 For instance, it took eggs of Chrysops callidus five or six days to 

 hatch, and it required about a day longer in the case where eggs 

 were kept in the shade the whole time, than in cases where the 

 eggs were in the sun during the daytime. 



Eggs of Tabanus stygius hatched in about seven days in each 

 of the two or three trials I gave them. In all species observed 

 all the eggs of a single mass hatch very near the same time, and 

 the whole mass of wriggling larvae go tumbling down into the 

 water together. Once in the water they separate and sink to the 

 muddy bottom, where they conceal themselves so securely that 

 they are not usually seen again until they appear as adults. Some- 

 tirnes there are a few eggs that are slow in hatching, and larvse^ 

 from these come out and drop to the water singly or in small 

 groups. 



., . , LARVA AND PUPA. 



The larvae of the different species of this family are very. 

 much alike in appearance, except in size, consequently the full 

 growm larvae of the small species are hardly distinguishable from 

 younger larvae of the large species. They are tapering at each 

 end, shining whitish in general color, and many of the larger 

 specimens at least, are banded with dark brown or black. 



