80 THE EARLY STAGES OF TABANID^ 



uniformly black color. About its early stages we are informed by 

 Walsh, C. V. Riley, Hart, and Hine. As Hine summarizes, the eggs 

 are deposited around marshy places on grass and sedges, and the 

 larvae are found by digging in the mud. 



Hart (1895) is the first to give notes about its oviposition, which 

 was noticed in Illinois, in July and August, and egg masses then be- 

 came frequent. The last date for the imago was August 15. On 

 August 1 1 , a female was observed ovipositing on the side of a wooden 

 frame standing over the water. The egg mass was placed in a breed- 

 ing cage, and one week later, on the 18th, many larvae hatched 

 from it. Another egg mass of the same form and appearance, placed 

 on the dark bark of a stick projecting from the water, was brought 

 in July 27, from which hatched on August 4 larvae apparently of 

 this species. 



Hart's description of the egg mass and egg is given below: 



"Egg Mass. — Blackish-brown, subconic, with oval base, 10-15 mm. long 

 and 8-10 mm. wide, height 5-7 mm.; sides convex or concave, apex correspond- 

 ingly rounded or pointed; eggs pointing obliquely upward and towards one 

 end, both sides meeting upon that end in a more or less prominent longitu- 

 dinal crest. The eggs are stacked in four or five tiers, one above another, and 

 gummed together into a firm mass." 



"Egg. — Length 2.5-2.7 mm., diameter 0.4 mm. Dark brown, subcylindrical, 

 ends more or less tapering and curved, surface minutely rugose and subopaque." 



Hine completed these observations in 1906. According to him, the 

 eggs of Tabanus atratus are generally placed in masses of various sizes 

 on the leaves and stems of grasses and sedges and other plants growing 

 in marshy or wet ground, but not necessarily in the water. A single 

 mass may contain as many as 500 eggs, but often they are smaller 

 and they may be larger; they are white when first placed, but soon 

 turn brownish. The mass is very convex and composed of several 

 layers, one above the other, the bottom layer being attached to the 

 surface of the leaf or stem and the other layers each to the one that 

 was placed before it. Each egg is elongate, spindle-shaped, between 

 2 and 3 mm. in length, and narrowed at each end. A female was 

 observed, in Ohio, ovipositing on June 23 at 11 o'clock. The eggs 

 were taken and kept in a room out of the sun, where they hatched on 

 the morning of July 2 before 6 o'clock, thus requiring an incubation 



